CIS: The Anonymous Japanese Day Trader Who Made $34M in 48 Hours from His Apartment

It was the twenty-fifth of August, two thousand and fifteen, just before two in the morning Tokyo time, and a thirty-six-year-old Japanese man in pyjamas was sitting in front of four computer screens in a room cluttered with manga, watching the Nikkei futures market melt down in real time. Over the previous twelve days he had quietly accumulated a short position of one thousand five hundred Nikkei contracts. The notional exposure was approximately two hundred and forty million American dollars. For every one hundred yen the index moved in either direction, he stood to make or lose one and a quarter million dollars.

By three p.m. Tokyo on the previous trading day, after the Nikkei had plunged more than one thousand points in a single session, his paper profit on the trade stood at thirteen million dollars. Most professional traders, on a private trade of that size, would have closed the position immediately and treated it as the year’s work. The thirty-six-year-old in pyjamas did the opposite. He added another two hundred contracts and went for a walk.

By ten o’clock that evening, with the United States markets in panic and the Nikkei futures down a further one thousand two hundred and fifty points from the Tokyo close, he closed the short. Profit on the short alone: twenty-seven million dollars. He then began selling deep out-of-the-money put options to investors who, in his judgment, were panic-buying insurance against a forty percent collapse in the Japanese index that he believed was almost mathematically impossible. By midnight he had reversed his entire position and accumulated a long futures bet of approximately one hundred and forty-five million dollars on the rebound. He sold a final batch of put contracts to late-night panickers, tweeted that he was going to bed, and slept for five hours.

When he closed the long position the following afternoon, his profit on the entire two-day trade was approximately thirty-four million American dollars. He tweeted, in Japanese, that the epic rebound trade was over.

The man’s real name has never been confirmed publicly. He goes by the internet handle CIS. He has given fewer than half a dozen interviews in twenty years of professional trading. He has appeared on Japanese television exactly once, in two thousand and eleven, with a translucent box on his head and his voice run through a modulator. He works alone, from a small rented apartment, with no employees, no fund, no investors, and no responsibilities to anyone other than his wife and three children. He has, by every available estimate, single-handedly compounded a fortune that begins with three million yen of capital in the early two thousands and ends, twenty years later, somewhere comfortably north of twenty billion yen.

He is the precise inverse of every investor profiled so far in this series. Where Anthony Bolton ran six and a half billion pounds at Fidelity over twenty-eight years through patient fundamental analysis, CIS runs his own money over decades through pure momentum, without ever reading an annual report. Where Jim Rogers crossed six continents on a motorcycle to look at countries, CIS rarely leaves his apartment during trading hours. Where Kerr Neilson refused to manage against any benchmark and held positions for three to five years, CIS holds positions for hours, sometimes minutes. He is, by professional fund management standards, almost a parody of everything wrong with retail trading. He is also, by his actual track record, one of the most consistently successful individual market participants in modern Japanese financial history.

CIS — AT A GLANCE
Real name	Never publicly confirmed; trades under handle CIS (株式会社CIS)
Born	Approximately 1979, Tokyo, Japan (age 36 in 2015 Bloomberg interview)
Pre-trading career	Industrial shock-absorber designer at small Japanese manufacturer (early 20s)
Started trading	Approximately 2000–2001, around age 21–22, with ~3 million yen starting capital
Method	Pure momentum: “buy stocks that are being bought, sell stocks that are being sold.” No fundamentals, no news, no indicators.
Primary instrument	Nikkei 225 futures (10x leverage); Japanese individual equities; options
2013 reported result	~¥6 billion after-tax profit; ~$14 billion in total Japanese equity turnover (~0.5% of all retail volume on the TSE)
August 2015 trade	~$34 million profit in a single 48-hour period during the Chinese-led global selloff
Estimated net worth	¥16–25+ billion (mid-2010s self-reported); estimates vary, public verification limited
TV appearance	2011 on “Waratte Iitomo!” with translucent box and voice modulator; only public appearance
Twitter	@cissan_9984 (formerly @cis_jp); ~40,000 followers in 2015, larger since
Mentor	Bibirion (“Coward King”), the 2channel trader who taught CIS to abandon fundamentals for momentum
Famous quote	“Not even Goldman Sachs can beat me in a trade.”
Book	2018 Japanese-language autobiography, roughly translated as The Investment Philosophy of a Man Who Can Single-Handedly Move Markets; Amazon Japan bestseller

Almost everything in the table above is, by professional standards of fund-management documentation, unverifiable. CIS has never been audited. He has never published a track record signed off by an accounting firm. He has never managed outside money. The numbers come from his own bank statements held up to television cameras, his own brokerage screenshots posted to Twitter, his own tax filings shown selectively to Bloomberg journalists, and the consistent pattern of his publicly time-stamped trade tweets over more than a decade. Every careful profile of him, including this one, has to acknowledge upfront that the verification standard is lower than for the institutional managers in this series.

What carries the case beyond folklore is the consistency. CIS has been narrating his trades publicly, in real time, since two thousand and seven. His Twitter feed, with screenshots time-stamped to the second, is one of the most documented retail trading records in modern Japanese financial history. The total fortune is contested. The trading skill, by every reasonable evidentiary standard short of a public audit, is real. He is the modern archetype of the Japanese hyper-individualist day trader, and any honest series on the greatest traders of our time has to give him a chapter.

The Shock-Absorber Engineer

The biographical details before two thousand and three are almost entirely missing from the public record. CIS, by his own brief Bloomberg account, was born around 1979 in or near Tokyo, attended a Japanese university whose name he has never disclosed, and graduated into a Japan still suffering through the long post-bubble recession of the 1990s. His first job, taken in the early two thousands when he was approximately twenty-one or twenty-two years old, was as a designer of industrial shock absorbers at a small Japanese manufacturer.

The detail of the first job matters. CIS did not begin in finance. He had no Wall Street internship, no investment-banking apprenticeship, no university economics training that he has ever publicly cited. He spent his early professional years sitting at a CAD workstation drawing the geometry of metal cylinders that absorbed kinetic energy in industrial machinery. He was, in every visible respect, an unremarkable young Japanese engineer. The skills he developed in that role, however, were precisely the skills that would later define his trading. He was technically literate. He was patient with detail. He had been trained, by the rigour of mechanical engineering, to think about systems in terms of inputs, outputs, energy flows, and failure modes. None of that vocabulary appears in his subsequent trading commentary. All of it is visible, on careful reading, in how he actually traded.

Around two thousand or two thousand and one, in his early twenties, CIS started trading Japanese stocks with a few million yen of accumulated savings. His own later account of the starting capital is approximately three million yen, roughly thirty thousand American dollars at then-current exchange rates. He has never publicly stated that the capital came from student loans, although that detail has occasionally been repeated in derivative profiles. The verifiable starting figure is the three million yen.

His first eighteen months were a disaster. CIS, by his own subsequent account, started trading the way most retail beginners start trading. He read Japanese fundamental analysis books. He bought what looked, by accounting metrics, like cheap stocks. He held them as they fell. He averaged down. He lost money consistently. The losses were not catastrophic, because the position sizes were small, but they were consistent enough to have driven most retail traders out of the market entirely within a year. CIS, by temperament and by something deeper than temperament, did not leave.

2channel, Bibirion, and the Lesson That Changed Everything

The pivot in CIS’s trading career came through 2channel, Japan’s anonymous textboard message system, which in the early two thousands was the closest thing the country had to a real-time community of self-taught retail traders. Sometime in two thousand and three, CIS encountered, on the 2channel stock-trading boards, a slightly older anonymous trader who went by the handle Bibirion. The handle translates roughly to “Coward King” in Japanese internet slang, a self-mocking reference to his risk-averse personality.

Bibirion had been trading since two thousand. He had developed a methodology focused on small-cap Japanese emerging-markets stocks listed on the JASDAQ and the Mothers Index. He used five-day and twenty-five-day moving averages. He tracked volume signatures rather than fundamentals. He cut losers fast and let winners run. By two thousand and three, his returns were extraordinary by any retail standard, and the 2channel community had begun to treat his anonymous posts as something close to gospel.

Bibirion and CIS met at the first 2channel offline meetup in Shinjuku in late two thousand and three or early two thousand and four. They became friends. CIS would later write, in his two thousand and eighteen book, that Bibirion was the first person to teach him how to trade profitably. The lesson, in CIS’s later summary, was almost embarrassingly simple. Stop buying cheap fundamentals, Bibirion told him. Buy what is being bought. Sell what is being sold. Watch the price action and the volume. Forget the company.

The lesson sounded trivial. In practice, for an engineer who had spent his entire professional life believing that careful analysis of underlying systems was the path to truth, it was a deep philosophical inversion. CIS had to learn to stop reasoning from first principles about the value of a business and start reading the language of supply and demand on the order book. Several months into trying to apply Bibirion’s framework, CIS started making money. He has, in interviews ever since, dated his real career as a trader to the friendship with Bibirion in two thousand and three.

The 2channel Years and the Trash-Talking Persona

Throughout the mid-two thousands, CIS built his fortune partly through trading and partly through cultivating a deliberately outrageous online persona on the 2channel stock boards. He posted screenshots of large daily profits. He mocked institutional traders. He wrote lines that became part of Japanese day-trading folklore. Not even Goldman Sachs can beat me in a trade, he claimed in one frequently quoted post. Excuse me while I go flush some cheap wine that only cost me eight hundred thousand yen, he wrote in another. The trash-talking, by every account from contemporary 2channel users, was understood by most participants as deliberate kayfabe rather than as actual arrogance. CIS was performing a character. The character was funny. The character was making money. The character became famous.

By two thousand and five he had moved from small-cap emerging-market stocks into Nikkei futures and Japanese banking sector momentum trades. The starting capital of three million yen had compounded into the tens of millions, then hundreds of millions. He had quit his job designing shock absorbers. He was trading from a small Tokyo apartment, alone, on a setup of multiple monitors connected to Japanese retail brokerage accounts.

The defining episode of those years, the one that established CIS’s reputation across the entire Japanese day-trading community, was the J-Com incident of December two thousand and five. On the eighth of December, two thousand and five, a junior trader at Mizuho Securities mistyped an order in the initial public offering of a Japanese recruitment company called J-Com Co. Instead of selling one share at six hundred and ten thousand yen, the trader sold six hundred and ten thousand shares at one yen each. The fat-finger error created an immediate, mechanical, and entirely riskless arbitrage opportunity for any trader fast enough to recognise it and click the buy button before the exchange suspended trading. CIS recognised it. He clicked. So did several other top Japanese day traders, including a younger trader who would soon become a household name in his own right, BNF.

The amounts CIS made on the J-Com fat finger have never been precisely disclosed. Some Japanese press accounts put the figure in the hundreds of millions of yen. The exact number is less important than the structural lesson. CIS had become, in his mid-twenties, one of the small handful of Japanese individual traders fast enough and connected enough to scoop several years of normal trading income off a single market accident in less than ninety seconds. That was the level he was operating at by the time most of his university classmates were three years into their corporate salary careers.

The Method, in CIS’s Own Voice

CIS’s method, by his own description across multiple Japanese-language interviews and the two thousand and eighteen book, has remained almost unchanged for twenty years. The components are easy to list and almost impossibly difficult to apply.

The first component is pure momentum. CIS does not read company financial statements. He does not subscribe to the Nikkei newspaper. He does not follow macroeconomic news. He does not use technical indicators in the conventional retail sense. He watches price and volume, in real time, on the Japanese equity and futures markets, and he positions himself in the direction the largest order flow is currently moving. Buy stocks that are being bought, sell stocks that are being sold is, in his repeated framing, almost the entirety of the strategy. The intellectual content of the method is in recognising, second by second, when momentum is real and when it is fading.

The second component is asymmetric position-sizing. CIS, throughout his career, has used the leveraged structure of Nikkei futures to scale into positions gradually as the trend confirms. He starts small, often with just a few contracts. If the trade moves against him quickly, he exits with a small loss and re-evaluates. If the trade moves in his favour, he adds aggressively, sometimes to hundreds of contracts and notional exposures of tens or hundreds of millions of dollars. The asymmetry is the entire economic engine of the strategy. The losses are clipped fast. The winners are scaled into.

The third component is fast, ruthless stop-losses. CIS has spoken in multiple interviews about the psychological foundation of this discipline. The losing trader, he argues, is the trader who refuses to admit error. The instinct to hold a losing position in the hope of break-even is, in CIS’s framework, the single most expensive mistake any retail trader ever makes. The emotion of not wanting to lose money, not wanting to admit to losing money, he has said, will lead to trading failure. He has acknowledged repeatedly that he has stopped out of trades that subsequently ran in the direction he originally predicted, and that this is acceptable, because the alternative, holding through a losing trade, costs more over the long arc.

The fourth component is exploiting other people’s panic. CIS’s most celebrated trades, including the August two thousand and fifteen one and an earlier episode during the March two thousand and eleven Tohoku earthquake, were not predictions of fundamental events. They were structural bets that other market participants, in a state of acute fear, would mis-price options or futures by a margin so large that the contrarian’s job was simply to take the opposite side. I do my best work when other people are panicking, he told Bloomberg in two thousand and fifteen, in the line that has been quoted more than any other from his career.

“I do my best work when other people are panicking.”

— CIS, August 2015

The Translucent Box on Japanese Television

By two thousand and eleven, CIS had been a major Japanese day-trading folk hero for roughly six years and had never appeared in any visual medium. The Twitter account had grown, the 2channel posts had become legendary, and his rumoured fortune had grown into the multi-billion-yen range. A Japanese television variety show, “Waratte Iitomo!” or “It’s OK to Laugh!”, convinced him to appear on national television in late two thousand and eleven on the condition that he would not be visually identifiable.

The producers built him a translucent acrylic box that fit over his head and shoulders. They ran his voice through a digital modulator that flattened the pitch into something between a robot and a malfunctioning intercom. He walked onto the set in this configuration. The studio audience reaction was immediate and electric. Who are you, the host asked. I am a man who made ten billion yen day trading, CIS answered through the modulator. The crowd erupted.

The actual figure, by CIS’s own subsequent admission, was closer to nine billion yen at the time. The producers had asked him to round up for television. The producers also held up, on camera, an enlarged statement from one of CIS’s bank accounts showing a balance of one billion two hundred and sixty-nine million two hundred and twenty-three thousand three hundred and sixteen yen. The display of the bank statement, more than the appearance itself, was the moment that converted CIS in the Japanese popular imagination from rumoured 2channel folklore into a documented public phenomenon. He has not appeared on television since.

The Twitter Years and the Bloomberg Profiles

CIS opened a Twitter account in around two thousand and ten and began using it as the primary channel for his real-time trade narration and his public personality. The account, currently @cissan_9984, has become one of the most followed retail-trader feeds in the Japanese-speaking internet. He posts screenshots of his trades. He mocks bad calls in real time, including his own. He talks about video games. He explains, briefly and often cryptically, what he is doing as the Tokyo and overnight U.S. sessions unfold.

In late two thousand and thirteen, Bloomberg published the first major Western profile of CIS. The journalist Jacob Adelman, working from Tokyo, had spent more than half a year in repeated meetings with CIS to verify trades against bank statements and tax filings. The Bloomberg piece reported a two thousand and thirteen after-tax profit of approximately six billion yen and a total accumulated fortune in the sixteen-billion-yen range. CIS had, that year, traded approximately fourteen billion American dollars in Japanese equities, accounting for roughly half a percent of all retail equity volume on the Tokyo Stock Exchange.

The second Bloomberg profile, published in August two thousand and fifteen during the Chinese-led global selloff, captured the thirty-four-million-dollar Black-Monday rebound trade described at the start of this article. The two Bloomberg pieces together, more than any other single source, established CIS’s international reputation. Translations into English, Russian, Mandarin Chinese, and German appeared within weeks. The mystique of the anonymous Japanese day trader who could move single names on the Nikkei from his pyjamas became one of the more durable retail-trading stories of the decade.

The Losses, Honestly Reckoned

CIS has been, by Japanese cultural standards, unusually open about his losing trades. The two thousand and fifteen Bloomberg interview included his explicit acknowledgement of a six-million-dollar loss earlier that year on the Greek debt crisis, where he had failed to monitor the news flow closely enough and had been caught on the wrong side of a sudden shift. The two thousand and eighteen book devoted significant space to a series of large drawdowns through his career, including an episode where he lost approximately one billion yen in a matter of days during the post-Lehman volatility of late two thousand and eight.

The pattern of the losses is consistent. CIS loses money when his momentum framework collides with a piece of macroeconomic or political information that he has not been tracking closely enough to anticipate. The strategy is, by design, news-blind. The strategy works because most short-term price action is driven by order flow rather than by news, and because being news-blind frees CIS to act on order-flow signals faster than news-aware traders. The cost of the strategy is that, several times in any given year, a piece of news appears that genuinely changes the underlying probability distribution of asset prices, and CIS, having ignored it on principle, takes a sharp loss before he can adjust.

The honest version of the CIS career, told by CIS himself in his two thousand and eighteen book, is not the version that survived in derivative blog posts and forum threads. The book is candid about the drawdowns, the emotional cost of the losing streaks, the marriage strain caused by the early years of obsessive trading, and the fact that he has stopped out of trades hundreds of times only to watch them subsequently run in his original direction. The CIS who emerges from his own writing is significantly more humble than the CIS of the 2channel persona.

The Frugal Billionaire

One of the more striking features of the CIS profile is how little his life has changed as his fortune has grown. He still trades from a small rented apartment, by all available accounts. He is married to the same woman he married before he was rich. They have three children who attend ordinary Japanese schools. He spends most of his recreational time, when not in front of the screens, playing video games and pachinko, the same activities he enjoyed as a twenty-two-year-old engineer.

His friend Uemura, also a successful Japanese day trader, summarised the philosophy in a Bloomberg interview. The kind of person who wastes money on that stuff would never have made it this far, Uemura said, referring to luxury consumption. Self-control is so important. You have to conserve your assets. That’s what insulates you from the downturns and gives you the ammunition to make money. The discipline of frugality, in the CIS framework, is not separate from the discipline of trading. They are the same discipline. The trader who panics in a market drawdown and the trader who buys a Lamborghini after a winning year are, at the level of psychological wiring, the same person.

In two thousand and sixteen CIS opened a small Tokyo casino called Casino Quest, with his old mentor Bibirion as a co-investor and president. The venture is by every account a hobby rather than a business. CIS still spends most of his time trading.

What We Cannot Know

The CIS profile carries genuine evidentiary problems that any honest treatment has to acknowledge.

The total fortune is uncertain. Self-reported figures from the mid-two thousand and tens placed CIS’s net worth in the sixteen-to-twenty-billion-yen range. Brokerage statements made available to Bloomberg in two thousand and fifteen showed liquid assets of between four point four and four point eight billion yen, materially less than the headline figure. The gap between the two numbers may reflect property holdings, additional accounts, or, possibly, some inflation in the public claims. We do not know, and we cannot verify.

The trading methodology has never been independently audited. CIS has consistently provided real-time tweets, screenshots, and selective tax documentation to journalists, but he has never submitted to a third-party performance review of the kind required of regulated funds. The trades that get tweeted are the trades CIS chooses to tweet. The trades that fail catastrophically and are quietly closed without comment are not part of the public record. The aggregate selection bias is real and impossible to quantify.

The starting-capital story has migrated. Some accounts state three million yen of personal savings. Others, derivative of these, have characterised the starting capital as student-loan money or as around thirteen thousand U.S. dollars. CIS himself has been consistent on the three-million-yen figure. The student-loan version appears to be a translation drift from English-language blogs and is probably wrong.

The “buy stocks that are being bought” methodology, as articulated by CIS, is genuine but partial. The verbal summary of the strategy is so compressed that any retail trader trying to copy it from the summary alone would almost certainly lose money. The actual edge, if there is one beyond luck, lies in the pattern recognition CIS has built across two decades of staring at Japanese order books for ten hours a day. That pattern recognition does not transfer through interviews, books, or tweets. It transfers, if at all, only through similar amounts of personal screen time. The CIS who emerges from any reading of the public material is better understood as a long-tenure specialist in one specific market structure than as a portable strategy that can be lifted and applied elsewhere.

The big question of whether CIS is genuinely skilled or extraordinarily lucky has never been definitively settled. The honest answer is that twenty years of consistently positive results, with documented intra-year drawdowns, is statistically very difficult to explain by luck alone in a market structure with as many active participants as Tokyo. The honest answer is also that the absolute size of the fortune is small enough, by global hedge-fund standards, that survivorship bias remains a non-trivial concern. The investors we hear about are almost always the ones who survived. The Japanese day-trading community of the early two thousands had thousands of participants. CIS is one of perhaps half a dozen who came out of it with multi-billion-yen fortunes intact.

What CIS Teaches

The first lesson, the one most often missed, is that pure momentum trading at retail scale is not a refutation of fundamental investing. It is a separate discipline operating on a separate time horizon with separate informational inputs. CIS does not disagree with Anthony Bolton or Kerr Neilson about whether intrinsic business value matters. He disagrees about whether intrinsic business value can be exploited at the time horizon he chooses to trade on, which is hours rather than years. The retail trader who tries to combine fundamental analysis with intra-day momentum trading is almost always trying to fight on two fronts at once and losing on both. CIS picked one front, in his early twenties, on the advice of a mentor, and never deviated. The lesson is the choice itself, not the choice of momentum specifically.

The second lesson is the cost of the news-blind strategy and the discipline required to accept it. CIS, by his own admission, takes large unanticipated losses several times a year because he has chosen, on principle, not to track macroeconomic or political news. The trade-off is that being news-blind allows him to act on order-flow signals faster than news-aware traders, and the cumulative speed advantage, over thousands of trades, more than offsets the news-blind drawdowns. Most retail traders try to have it both ways, blending fundamental conviction with technical timing in a way that produces neither edge cleanly. CIS chose. The choice cost him several million dollars in any given year. It made him the rest.

The third lesson is about the relationship between discipline and personality. CIS is, by his friends’ descriptions, an unusually phlegmatic person. He plays video games to calm his nerves before large trades. He eats carrots. He sleeps for five hours after a thirty-four-million-dollar trade and goes back to work. The stoicism is not a pose. It is the underlying psychological infrastructure that makes the rest of the methodology workable. The retail trader who tries to copy the CIS method without copying the CIS temperament is missing, by a wide margin, the most important variable. Maybe it’s the simple fact that he doesn’t get rattled, his friend Masahiro Kawata told Bloomberg. The fact that he does not get rattled is not separate from the fact that he makes money. It is the thing that makes the money.

The fourth lesson, the deepest, is that the public market is a structure where genuine retail edge can still exist for the right person under the right conditions. The post-2008 institutionalisation of global equity markets has made the retail trader’s life harder almost everywhere. The Japanese day-trading community of the early two thousand and tens was a partial exception. The combination of the Bank of Japan’s monetary stimulus, the relaxation of margin lending limits, the structural inefficiencies of an aging Japanese retail investor base, and the very high volume of small-cap Mothers and JASDAQ stocks created a window in which a tiny number of extraordinarily disciplined individual traders could compound capital at rates institutional managers could not match. CIS, BNF, and a handful of others, working from apartments and bedrooms with retail brokerage accounts, exploited that window for over a decade. Most of those windows close. The CIS lesson is not that the window will reopen for the next retail trader on demand. The lesson is that windows of this kind do open occasionally in markets, that they are usually obvious in retrospect and invisible while they exist, and that the traders best positioned to exploit them are the ones who have spent years in screen time when the window was closed.

Frequently Asked Questions

Who is CIS?

CIS, also written 株式会社CIS in Japanese, is the internet handle of an anonymous Japanese day trader who has become one of the most famous individual market participants in modern Japanese financial history. He has never publicly disclosed his real name. He was approximately 36 years old in his 2015 Bloomberg interview, suggesting a birth year around 1979. He has worked as a full-time individual trader since approximately 2003, primarily in Japanese equities and Nikkei 225 futures. His Twitter handle is @cissan_9984. He has given fewer than half a dozen substantive interviews in his career and made only one TV appearance, in 2011, with his face hidden by a translucent acrylic box.

How much has CIS made?

The figures are self-reported and partially verifiable. CIS’s most consistent claim is a total accumulated fortune of approximately ¥16 billion to ¥25 billion across his career, depending on which interview is being cited. Brokerage statements he made available to Bloomberg in 2015 showed liquid assets of between ¥4.4 billion and ¥4.8 billion. He reported a 2013 after-tax trading profit of approximately ¥6 billion and a total turnover in Japanese equities of approximately fourteen billion American dollars that year. He reported a thirty-four-million-dollar profit on a single 48-hour trade during the August 2015 global selloff. None of these figures has been independently audited by a third party.

What is CIS’s trading method?

Pure short-term momentum trading. CIS does not read company financials, follow macroeconomic news, or use traditional technical indicators. His method is summarised in his own phrase: “Buy stocks that are being bought, sell stocks that are being sold.” He watches order flow and volume in real time on the Tokyo Stock Exchange and the Osaka Securities Exchange (Nikkei futures), takes positions in the direction of the largest current flow, scales aggressively into trades that work, and stops out fast on trades that do not. His holding periods range from minutes to a few days. His primary instrument is the Nikkei 225 futures contract, traded on approximately ten-times leverage.

What is the J-Com incident?

On the eighth of December 2005, a junior trader at Mizuho Securities mistyped an order in the IPO of a Japanese recruitment company called J-Com Co. Instead of selling one share at six hundred and ten thousand yen, the trader sold six hundred and ten thousand shares at one yen each. The fat-finger error created a near-instantaneous, mechanically riskless arbitrage for any trader fast enough to recognise it before the exchange suspended trading. CIS, alongside several other top Japanese day traders including BNF, made a substantial profit in less than a few minutes. The incident is one of the most famous events in Japanese retail trading history and helped establish CIS’s reputation across the broader 2channel community.

How did CIS appear on Japanese television?

In late 2011, CIS appeared on the Japanese variety show “Waratte Iitomo!” (“It’s OK to Laugh!”). To preserve his anonymity, the producers built him a translucent acrylic box that covered his head and shoulders, and he spoke through a digital voice modulator. He told the host he had made ten billion yen day trading. The actual figure at the time was approximately nine billion yen, by his own subsequent admission, but the producers asked him to round up for television. The producers also held up, on camera, an enlarged statement from one of his bank accounts showing a balance of approximately ¥1.27 billion. It remains his only public television appearance.

Did CIS write a book?

Yes. In late 2018 CIS published a Japanese-language autobiography, the title of which translates roughly as The Investment Philosophy of a Man Who Can Single-Handedly Move Markets. The book reached the Amazon Japan bestseller list within days of publication. It covers his early career as a shock-absorber engineer, his pivot to trading through 2channel and the friendship with Bibirion, his methodology, several of his most famous trades, and several of his largest losses. To date, no authorised English translation has been published.

Is CIS comparable to BNF?

BNF, real name Takashi Kotegawa, and CIS are usually mentioned together as the two most successful individual day traders to emerge from the Japanese 2channel community of the mid-2000s. They knew each other personally from 2channel offline meetups. They both made substantial profits on the December 2005 J-Com fat-finger incident. Their methodologies, however, are different. BNF specialised in short-term mean-reversion trades on Japanese individual equities, holding positions typically for a few days. CIS specialised in directional momentum on Nikkei futures, with much shorter holding periods and significantly higher leverage. Both retired into the Japanese super-wealthy class in their thirties. BNF is even more reclusive than CIS and has not given interviews in more than a decade.

Can CIS’s method be copied?

The verbal summary of his method can be copied. The actual edge, if it exists beyond market-cycle luck, almost certainly cannot. CIS’s pattern recognition was built over approximately twenty years of staring at Japanese order books for ten or more hours a day, in a specific market structure with specific liquidity dynamics that have since changed substantially. Retail traders attempting to copy the “buy what is being bought” rule from a translated tweet, without the underlying screen time, the underlying temperament, and the underlying market structure, almost always lose money. The portable lesson from the CIS career is the discipline of method specialisation, the discipline of fast stop-losses, and the discipline of frugality in personal life. The portable strategy is significantly less than that.

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