This article is part of a new series on Gaming Alexandria called Origin of Game, stories of how famous game companies came to be! These tales written by staff and guest authors draw on research gathered over the years and give a glimpse into the people who defined video game history. We hope these articles will stoke your desire to learn more about the developers and publishers who have made our world fun!
Late at night in the city of Ashikaga, in the cramped office above a warehouse floor, a man sat alone with his father’s ledger books. Outside, the Watarase River ran dark through a city that had once hummed with the clatter of looms and the chemical bite of dye vats. Ashikaga had been textile country for generations — a place where families like the Erikawas measured wealth in bolts of silk and the deep indigo of freshly dyed cloth.
The numbers in those ledgers told a story that nobody wanted to say aloud. The customers were gone.
The workshops along the river had closed one by one, pulled under by cheaper imports from Southeast Asia. Each failure dragged the next business down — rensa tōsan, chain bankruptcy — until the whole chain lay broken.
Yoichi Erikawa was twenty-eight years old. He had come home because his father told him to — two words, modotte koi, “come back” — and because in 1970s Japan, when your father said come back, you came back. What he found when he arrived was not a business to inherit, but one to bury. Within three months of his return, the family dye business that his grandfather had founded before the war was gone.
But this story does not begin with Yoichi. Or rather, it does not begin with him alone.
The company that would become Koei (the studio behind Nobunaga’s Ambition, Romance of the Three Kingdoms, Dynasty Warriors, and Pokemon Pokopia) was built by two people whose talents fit together like interlocking gears.
To understand how a failing dye merchant in a provincial Japanese city created a new genre of video game, you have to understand both of them. Keiko Erikawa’s story is different.
She was eighteen, seated at a pachinko machine, one eye squinted against the curl of cigarette smoke, five or six boxes of steel balls stacked at her feet. The parlor was loud, bright, and no place for a teenage girl — a room for men on their lunch breaks, retirees killing afternoons, and the occasional delinquent skipping school.
Former classmates remembered her childhood differently: a picture of privileged refinement, “like a French doll,” the only child doted on by a family of doctors and dentists. Born in 1949, Keiko had initially arrived into comfort. Her New Year’s money in elementary school totaled one hundred thousand yen — a staggering sum for a child at the time. She saved all of it.
That instinct traced back to her grandmother, who had taught Keiko a maxim she would carry for life: “Only fools lose money on stocks.” Her grandmother was not offering a warning. She was issuing an invitation. By eighteen, Keiko was investing in equities and reading the market pages with the intensity other teenagers brought to fashion magazines.
The pachinko was rebellion. Her family had mapped a future requiring neither ambition nor independence: junior college, then a receptionist job to improve her marriage prospects. Her mother turned off the lights at night and told her to sleep rather than study. A woman who could support herself would have no reason to stay married.
But beneath the rebellion lay something harder. When Keiko was six, her father died. Her mother moved the family to a mountain village in Gunma Prefecture. For three years, Keiko walked four kilometers to school through blizzards and along cliff faces, past a ravine where local children had died. The other kids singled her out as a city girl, bullying her daily. She brought her grandfather’s hunting dogs for protection. She never reported any of it. She learned to be firm and self-sufficient.
Against her family’s wishes, she enrolled at Tama Art University in the Graphic Design department. The competition ratio stood at thirty-three applicants per one seat. She passed on her first attempt. When campus lockouts shut down classes for months (part of the student protest movement sweeping Japanese universities in the late 1960s), Keiko found paying work — illustrating for a children’s television program, designing window displays for Mitsukoshi, collaborating on a Kanebo cosmetics campaign. By the time she graduated in 1971, she held a portfolio most graduates would spend years assembling.
Three hundred kilometers northeast, Yoichi Erikawa was building radios.
Born in 1950, the eldest son of dye merchants in Ashikaga, Yoichi had spent his childhood assembling vacuum tube radio receivers from kits and devouring electronics magazines. His first obsession was circuits, his second became history.
But when the time came to choose a university, his father intervened. A dye merchant’s son did not need engineering. He needed commerce. Yoichi complied, enrolling at Keio University and burying his disappointment in jazz. He played bass in a band called The Kalua — good enough to press an album with Toshiba. He was a young man who had not yet found anything worth taking seriously.
Yoichi and Keiko met at a boarding house. Keiko’s family home in Hiyoshi held more rooms than the family needed, and her mother rented the upper floors to boarders. Yoichi moved in through the most prosaic channel imaginable: the Keio housing office. “Ah, she’s here again,” Yoichi would think when he spotted Keiko at a nearby pachinko machine, smoke veiling her face.
The first real conversation happened at two in the morning on the staircase. Keiko was finishing an illustration deadline. Yoichi came home tipsy and invited her to a friend’s bar. She had declined his previous invitations, assuming he wanted her to buy tickets for his band. This time, exhausted and paint-stained, she said yes.
Yoichi would later describe their courtship with deadpan humor: “The boarding house daughter dangled a fishing line from the second floor, and I got hooked.” The image is deliberately self-deprecating — the great businessman as a fish who swam into an obvious trap. Keiko was the one with the plan, the savings, the instinct for action. Yoichi was the one who floated until something caught him.
Her family opposed the match — they wanted a mukoyōshi, an adopted son-in-law who would take the family name. The couple married anyway, just after Yoichi finished university. Keiko set one condition: she would continue working.
So when Yoichi’s father summoned them to Ashikaga and the dye business collapsed, it was Keiko who held things together. Yoichi drove to the hospital and found his father crying… not from physical pain, but from the knowledge that everything he had built was gone. “A company is a living thing,” Yoichi said years later. “I witnessed firsthand a living, vibrant company become nothing at all.”
Keiko did what she had always done: she broke the problem into parts and solved each one. She found an apartment near the hospital. She sold stocks from the portfolio she had been building since her teenage years. She bought a villa in the mountains for Yoichi’s parents — a place to rest, away from the city where the business had failed. The villa would become Koei’s first office.
Because Yoichi, against all reason, started a new dye company. He called it Koey — a name suggested by an I Ching diviner who studied the characters in Erikawa’s name and counseled: do not name the company after any particular industry. The meaning he gave was not the standard “glory” but something stranger: 光栄, “to flourish in solitude.” Keiko, drowning in work and childcare, told him to just go with it.
For two years, Koei limped along as a dye company. Yoichi stared at the same ledger-book arithmetic that had defeated his father. He considered folding the business — he had an offer to return to his old employer in Osaka. And then one day, at a bookstore, he picked up a magazine.
It was about personal computers. In 1980, this was still a niche interest in Japan — the domain of hobbyists who read publications like ASCII and I/O. The machines were expensive, arcane, and to a certain kind of mind, irresistible. “There’s a dream-like box,” Yoichi told Keiko over dinner. Night after night he pitched the computer’s potential: payroll, inventory, quotations. Keiko noted, with private amusement, that the payroll pitch was ambitious given that Koei had exactly one employee.
For Yoichi’s thirtieth birthday (October 26, 1980) Keiko bought him a Sharp MZ-80C. She paid for it from savings accumulated since her student days, including proceeds from selling several thousand shares of Nintendo stock — the Kyoto playing-card company that most investors still regarded as a modest manufacturer of toys. The computer cost 268,000 yen; Yoichi’s salary was 55,000 yen a month. For a household in financial distress, it was an extraordinary act of faith — not in the machine, but in him.
He had no programming experience. He was bunkei — a humanities graduate. The MZ-80C shipped with a built-in BASIC interpreter, but BASIC does not yield its logic to enthusiasm alone. He sat with the manuals. He typed commands. The machine froze. He learned the way everyone learned in 1980 — by breaking things and building them again.
The routine split his days in two. During daylight hours, he wrote financial software for the dye business. At night, after the household fell quiet, he wrote games. “Programming became my creative outlet,” he said.
He had grown up surrounded by and obsessed with Sengoku history, the Warring States period, and he wanted a game that would let him step into that world. Not as a character dodging projectiles, but as a strategist weighing alliances and commanding armies. No such game existed.
“There were no games that made use of history, so I had no choice but to make one myself.”
He called it Kawanakajima no Kassen (the Battle of Kawanakajima), depicting the sixteenth-century rivalry between Takeda Shingen and Uesugi Kenshin. Alongside it, Keiko contributed the idea for Investment Game — a stock market simulation built on her own financial sensibility. One game for the history obsessive, one for the financial mind. The pairing was a portrait of the marriage in software.
They shipped both titles on cassette tape in October 1981. There was minimal game industry infrastructure — virtually no publishers or distributors. Magazine ads were how hobbyist software reached its audience.
The Erikawas found an affordable ad placement in the back of Micom Magazine to advertise their two new games. Interested buyers mailed cash in envelopes. Yoichi expected to sell maybe a hundred copies. Instead, envelopes started arriving in cardboard boxes — cash from across Japan. The final sales reached nearly ten thousand copies. At 3,500 yen each, that was thirty-five million yen — more than seventeen times Koei’s entire starting capital.
Keiko ran every part of the operation that was not programming. She recruited neighborhood women to help duplicate tapes on rows of data recorders. She designed the packaging, hand-lettering the “Koey Microcomputer Systems” logo. For their first “red box” games, she cut photographs of the Falklands War from a newspaper and used them to frame a game about sixteenth-century Japanese warlords. “It was really quite careless!” she recalled. Two people building an enterprise out of whatever was within arm’s reach. In a way, this decision led to Koey’s first World War themed games, Combat and Das Boot.
Then came the moment that changed everything — not a sale, but a phone call. A furious customer rang to say the software did not work. Yoichi, who was also the entire customer support department, talked him through cleaning the tape head with a cotton swab and alcohol. Five minutes of silence. Then: “It worked!” The next day, the same man called back, his tone completely transformed. “The game was so fun I was up all night! Make more fun games!”
I was up all night. The phrase stopped Yoichi cold. The dye trade had never generated a single phone call of thanks. Chemicals vanished into someone else’s process — anonymous, untraceable. But here was a random stranger calling to say that something Yoichi had built had kept him awake until dawn. “It was an emotion I had never experienced before,” he wrote. For a man who had spent years selling dye chemicals, this was not revenue. This was connection.
Keiko saw where the numbers pointed. “It’s better to put all your effort into what you love,” she told him. Yoichi’s father opposed the idea — the dye trade was what three generations of Erikawas had built. But the arithmetic was merciless: the dying industry on one side of the ledger, the thriving software development on the other, the gap widening with every release. Yoichi handed the remaining dye operations to a colleague and closed the book on the family business.
The early catalog included titles that would later prove embarrassing: erotic games like Night Life, Seduction of Condominium Wives, and Do Dutch Wives Dream of Electric Eel? These were commercial products in the early 1980s PC market, where adult software sold reliably. The revenue helped sustain the company during the lean years before Nobunaga‘s breakthrough.
After nearly two years of the “Red Box” games and their mini-game compilations, the next game Yoichi designed was his most ambitious. Yoichi had read Shiba Ryōtarō‘s novels and felt the pull of their central question: what would it be like to be Oda Nobunaga? Not to read about him, but to stand in his position and make his choices.
“Everyone experiences their own ‘What if,'” he wrote. “What if I were Nobunaga? How would I fight, what kind of country would I build? I wanted to experience such ‘what if’ scenarios. Let’s turn that into a game.”
Yoichi made games that he himself wanted to play.
Nobunaga no Yabō — Nobunaga’s Ambition — released on March 30, 1983. The insight that separated it from Kawanakajima was not tactical but conceptual. This was not a battle simulation. It was a management simulation wrapped in a historical war game. The player governed a domain: rice production, flood control, diplomacy, the cultivation of subordinate lords.
“There should be no difference between a sengoku warlord, a manager, and a company department head,” Yoichi observed. He had spent years managing a failing business, watching his father manage one before him. He put all of it into the game.
The “what if” was more than a game mechanic — it was a philosophy of history. The scenario that obsessed Yoichi was Honnō-ji: the night in 1582 when Akechi Mitsuhide betrayed Nobunaga, ending the unification of Japan in fire and treachery. What if Nobunaga had survived? What alliances, what wars, what nation might have emerged? “Rather than playing games according to history, we’ve made it fundamental to create new history yourself,” Yoichi said. Every Koei simulation was an invitation to rewrite the past. The player was not a spectator. The player was the author.
That same year — 1983 — Yoichi and Keiko made a declaration. “If we’re going to do it, we should aim to be the best in Japan — no, the best in the world,” Yoichi wrote. They would aspire to become the world’s number one game company. “Just like Oda Nobunaga, who harbored the ambition to unify the country.” It was reckless. The company had a handful of employees in a provincial city no one associated with technology. But both founders shared the instinct: if you’re going to build something, build it to be the best. The ambition had Nobunaga’s own scale.
Keiko shaped the business around it. She suggested the pen name “Kou Shibusawa” — evoking Eiichi Shibusawa, the Meiji-era father of Japanese capitalism — positioning the work not as mere entertainment but as simulation.
She set prices high. “I didn’t want to sell cheaply what my husband poured his heart into making,” she said. Koei games cost more than competitors’ products — a deliberate signal of quality that would define the company’s commercial instinct for decades. She negotiated a distribution deal with Masayoshi Son’s SoftBank. The division of labor was fully visible now: Yoichi created, Keiko built the business that sustained those creations.
By 1985, the transformation was complete. Romance of the Three Kingdoms expanded the formula from Japanese history to Chinese classical literature. Genghis Khan pushed the map to the Eurasian steppe. The Famicom version of Nobunaga eventually sold half a million copies.
Fans who played the games in college applied for jobs at Koei; some of those early hires are still at the company four decades later. The games created the audience that created the workforce that created the next generation of games.
Years later, long after the ambition had reshaped an industry, Yoichi was asked what kept him going. “I love playing games, so I play all sorts of them,” he said. “Games are air to me. I cannot live without them.” At seventy-two, he was still playing two to three hours every night — working through Wo Long: Fallen Dynasty, a punishing action game made by his own company. When the deflect timing felt off, he had the developers extend the parry window by one frame. A sixtieth of a second. The man who had started with BASIC on a Sharp MZ-80C was still reaching into the code, still testing, still playing. He got more satisfaction from 100% completing a game than from making one.
Keiko saw further still. “Half of humanity are women,” she told Yoichi. “Games aren’t just for men.”
In 1983, the same year they declared their ambition to be the best in the world, she began hiring women. Not programmers (there were almost none), but writers and planners from the humanities. The goal was a game made for women, by women.
It took a decade. She assembled an all-female development team called Ruby Party, and in September 1994 they shipped Angelique — a romance simulation RPG where the player was the heroine, the first game of its kind. Within the company, skeptics said the market was too small. “There is a market,” Keiko insisted. She had held that conviction for ten years. Most executives would not have waited three.
Angelique was not an instant blockbuster. But the letters poured in — women who had never seen a game that acknowledged their existence, writing to say, ‘This is a great job you’ve done here for us.’ The game spawned sequels, drama CDs, anime, live events. Keiko had created not just a product but a genre — otome games, romance simulations targeted at women — and with it, a pipeline for women to join the game industry. An entire category of entertainment, born because one woman refused to accept that games belonged to men.
And beneath it all, there was the portfolio. The stocks Keiko had been buying since she was eighteen (her grandmother’s lesson made operational) had grown Koei into an institutional-scale investment operation. By 2024, non-operating investment income totaled 35.7 billion yen, exceeding the company’s operating profit from games. A Japanese business magazine called Koei Tecmo “an investment company that makes games.” The portfolio Keiko had started building as a teenager now shielded the company through every downturn in the game market.
The name 光栄, chosen almost by accident on registration day, kept proving perfect. To flourish in solitude. They had done exactly that: Yoichi’s “what if” imagination and Keiko’s self-sufficient financial vision, joined at the root, growing in different directions, sheltering the same company. He built worlds where players could rewrite history. She built a structure that ensured there would always be a next game. Both ambitious, both driven, both convinced that if you wanted something done right, you had to build it yourself — from a dining table where a husband programmed through the night while his wife illustrated logos beside him while cassette duplicators hummed against the far wall.
In 2024, a journalist asked Keiko whether they had achieved their dream — whether Koei Tecmo had become the best in the world. She answered with a single phrase: “Not yet.” The dye merchant’s ledger books were closed now, set aside somewhere in Ashikaga. In their place was an empire built by a Japanese couple’s complimentary skills, ruthless dedication, and their mutual, Nobunaga-sized ambitions.
Sources
Primary Sources
Yoichi Erikawa, The Power to Create: From Zero to One (ゼロから1を創造する力), 2017. JA. The single most important source — covers founding, Kawanakajima, “best in the world” declaration, Nobunaga development, “what if” philosophy, management simulation insight, 500K Famicom copies, “Half of humanity are women.”
Interviews — Yoichi Erikawa
GameBusiness.jp, “From Reviving the Family Business to Microcomputers,” Kurokawa Fumio, 2016-03-07. JA. URL: https://www.gamebusiness.jp/article/2016/03/07/12045_2.html. Ashikaga dye family, Keio, MZ-80C birthday gift, self-taught programming, Kawanakajima, RotTK.
Game Archaeology / Note.com, “Entame Ijinden Vol.7 — Yoichi Erikawa,” Kurokawa Fumio, 2021. JA. URL: https://note.com/game_archeology/n/n508a09e61e26. Founding story from Yoichi’s POV, MZ-80C, Kawanakajima, 夢の小箱 quote, band name.
4Gamer, “Yoichi Erikawa Lecture at University of Tokyo,” 2018-07-19. JA. URL: https://www.4gamer.net/games/999/G999905/20180714032/. Ashikaga textile collapse, chain bankruptcy, founding with 2M yen capital, PC encounter.
4Gamer, Shibusawa Kou 40th anniversary interview, 2023-03-28. JA. URL: https://www.4gamer.net/games/561/G056198/20230328015/. Wo Long 2–3 hours nightly, one-frame parry window, “games are air to me” context, Nioh lineage.
4Gamer, Shibusawa Kou 40th Anniversary Concert report, 2023-04-08. JA. URL: https://www.4gamer.net/games/666/G066636/20230410073/. “Games are air to me. I cannot live without them.” direct quote.
Dreamgate, “The 125th: Koei Tecmo Holdings — President Yoichi Erikawa,” 2011-04-06. JA. URL: https://www.dreamgate.gr.jp/contents/case/interview/35739. Band name “Kahlua,” entrepreneur profile.
Denfaminicogamer, “Koei Tecmo President Yoichi Erikawa Interview,” 2025-03-12. JA. URL: https://news.denfaminicogamer.jp/interview/250312b. Birth date October 26, 1950.
Oricon, “Nobunaga’s Ambition 40th Anniversary Feature,” 2023-03-30. JA. URL: https://www.oricon.co.jp/special/62856/.
AUTOMATON, “Koei’s founder on solo passion project at dawn of PC gaming.” EN. URL: https://automaton-media.com/en/news/there-was-no-such-thing-as-a-game-industry-back-then-koeis-founder-on-how-his-solo-passion-project-sold-10000-copies-at-the-dawn-of-pc-gaming-in-japan/. Kawanakajima sold 10,000 copies.
Shmuplations (trans. of BEEP! magazine, May 1988), “Koei: Designing Historical Games,” 1988-05-01. JA/EN. URL: https://shmuplations.com/koei/. Game design philosophy.
Archipel, “Interview with Yoichi Erikawa (Kou Shibusawa),” 2021. EN (video). Founding, Kawanakajima, Nobunaga, RotTK, regret about English.
Interviews — Keiko Erikawa
Game Archaeology / Note.com, “Entame Ijinden Vol.6 — Keiko Erikawa,” Kurokawa Fumio, 2021. JA. URL: https://note.com/game_archeology/n/n508a09e61e26. Keiko’s biography: childhood, father’s death, Gunma, Tama Art 33:1, pachinko, grandmother’s stocks, courtship, fishing-line quote, founding.
Sakaiya Taichi, “Everything Started from ‘Love'” in 12 People Shape Tomorrow (明日を企てる12人), Asahi Shimbunsha, 2002. JA. ISBN 4022577371. URL: https://www.amazon.com/people-attempt-tomorrow-ISBN-4022577371/dp/4022577371. Keiko’s POV on founding, MZ-80 purchase (¥400K figure), setting wholesale prices.
Famitsu (trans. KarasuCorps), “Pioneer of Games Marketed Toward Women,” 2015-06-29. JA/EN. URL: https://karasucorps.wordpress.com/2016/04/09/translation-an-interview-with-keiko-erikawa-the-pioneer-of-games-marketed-toward-women/. Angelique, Ruby Party, “There is a market,” hiring women from humanities 1983, decade to first game.
Famitsu, “Neoromance 30th Anniversary: Keiko and Mei Erikawa,” 2024. JA. Women’s gaming evolution, Ruby Party.
Daily Shincho, “Satō Masaru × Keiko Erikawa Interview,” 2022-02-08. JA. URL: https://www.dailyshincho.jp/article/2022/02080555/?all=1&page=3.
Interviews — Joint
Denfaminicogamer, “From Nobunaga to Otome Games: Kou Shibusawa and His Wife on Koei’s Rise,” 2016-03-22. JA. URL: https://news.denfaminicogamer.jp/projectbook/koei. Joint interview: MZ-80C gift, Kawanakajima, premium pricing, Angelique, Masayoshi Son, Nintendo stock (3,000–4,000 shares at ¥470).
Interviews — Mei Erikawa / Ruby Party
B’s-LOG, “Ruby Party Brand Director Mei Erikawa on Otome Games — Part 1,” 2018. JA.
B’s-LOG, “Mei Erikawa on Otome Games — Part 2,” 2018. JA.
4Gamer, “Angelique Luminarize Developer Interview: Mei Erikawa,” 2021-08-04. JA.
Contemporary Sources (1980s)
LOGiN Magazine, “Koei Company Visit,” 1986-07. JA. Hiyoshi HQ, ~30 staff, Keiko as executive managing director, MZ-80K noted, September 1984 Ashikaga→Yokohama relocation.
Akiba PC Watch, Sharp MZ-80 advertisement. JA. URL: https://akiba-pc.watch.impress.co.jp/docs/column/retrosoft/1099919.html. Confirms the machine Keiko bought.
Secondary Sources / Analysis
Gendai Media, “Keiko Erikawa Investment Technique.” JA. URL: https://gendai.media/articles/-/141328. 1.6 trillion yen portfolio, “investment company that makes games,” toshi no tensai.
MoneyPost, “Keiko Erikawa New Subsidiary President,” 2025-02-01. JA. URL: https://www.moneypost.jp/1246030. Non-operating revenue 35.7B yen exceeding 28.4B yen operating profit, Koei Tecmo Corporate Finance subsidiary.
Toyo Keizai, “Koei Tecmo Beyond-Keiko Era.” JA. URL: https://toyokeizai.net/articles/-/917723. Keiko investing since 18, datsu karisuma coverage.
Nintendo Life, “A Kou Shibusawa Production,” 2023-06-18. EN. URL: https://www.nintendolife.com/features/a-kou-shibusawa-production-changing-history-with-koei-tecmos-og-strategy-studio. Shibusawa pen name origin, franchise history.
Yahoo News Japan, “Growth of a Game Company Supported by Asset Management of 120 Billion Yen,” 2022-02-08. JA. URL: https://news.yahoo.co.jp/articles/fe7e9403fc476a1d1d03c49fb090f9925909514a. Keiko’s investment operation.
Official / Institutional
Koei Tecmo, “沿革 — Official Corporate History.” JA. URL: https://www.koeitecmo.co.jp/company/history/. Corporate timeline.
Koei Tecmo, “Kou Shibusawa Archives.” JA. URL: https://www.gamecity.ne.jp/shibusawa-kou/archives.html. Definitive game catalog 1981–2012.
Koei Tecmo, “Famous People Congratulate Yoichi Erikawa on 40th Anniversary,” 2021-10-26. JA. URL: https://www.gamecity.ne.jp/shibusawa-kou/thanks.html. Miyamoto, Horii, Son congratulations; confirms Kawanakajima first release Oct 26, 1981.
Koei Tecmo, “FY2024 Annual Presentation Materials,” 2024-12-31. EN. URL: https://www.koeitecmo.co.jp/e/ir/docs/ir3_20250602_01_e.pdf. Financial data.
Video Sources
YouTube, “Kou Shibusawa — The Dream Small Box (Part 1),” 2019-03-24. JA. URL: https://www.youtube.com/watch?v=SwZeTA6419g.
YouTube, “Kou Shibusawa — Message to the Next Generation (Part 2),” 2019-03-26. JA. URL: https://www.youtube.com/watch?v=eoD1SMsGshs.
YouTube, “She Challenged Nintendo and Opened Up the Female Game Market — Otome Godmother Erikawa Keiko,” 2022-03-14. JA. URL: https://www.youtube.com/watch?v=UidVHCUOXy4.
YouTube, “Yoichi Erikawa, the Origin of Koei” (Dead or Alive Festival 2016), 2021-09-29. EN. URL: https://www.youtube.com/watch?v=boLx7t4x2l8.
Famitsu, “Kawanakajima Started from Nintendo Stock Sale?” 2025. JA. URL: https://www.famitsu.com/article/202601/62602.
