Take Me to Koshien: ¥12.9M in 11 months, and the ¥100 ticket that multiplied IAP revenue by ten

Take Me to Koshien, a phone game where you coach a high school baseball team toward the national tournament, earned ¥12.9 million between its November 2017 release and the end of September 2018, eleven months in total. The best single month was August 2018 at ¥2.57 million. That figure is exactly ten times the ¥250,000 median among the 19 mobile apps on this site that disclose monthly revenue, and ten times the ¥250,000 median across our 88 Japanese cases. The author is Yu Furuta of furuApplications, a solo developer based in Nagoya, and this was the third baseball title in his series. The numbers invite a simple reading: the subject matter sold the game. Yet when App Marketing Institute asked him what changed the purchase revenue, he did not point to any item that hands players a stronger athlete. He pointed to a ¥100 ticket that lets you keep the third-year students who graduate and vanish when summer ends.

The third title, with retirement on the line

Furuta was already earning ¥300,000 a month from the previous title, but with a wife and child he felt that number would eventually stop being enough. He gave the third game a condition: if it did not reach ¥1 million a month within a year, he would quit app development. His own blog says the earlier title left no financial slack and that this one had to beat it.

The revenue split is 76% purchases and 24% advertising. Of the 48,000 downloads, 40% were iOS and 60% Android. Revenue per download came to about ¥260, the paying share was 5–6%, and each payer contributed roughly ¥3,000. One player in twenty pays ¥3,000 while the other nineteen watch ads or pay nothing at all. On his blog Furuta writes that playing for free until the day you uninstall is completely fine by him.

What sold was not the player, but the deadline attached to him

Furuta credits the draft ticket for the jump in purchase revenue. Because the game is set in high school baseball, third-year students retire after the summer tournament and leave your roster for good. The ticket, priced around ¥100, guarantees that a graduating player can be registered to your alumni team. After it shipped, purchase revenue rose tenfold and monthly sales went from the hundreds of thousands of yen to over ¥1 million. In his words, “psychologically, the motive to avoid losing something may be stronger than the motive to acquire it.”

Here is how we read that number. The ticket sold not because the audience loves baseball but because the game borrows its clock from the subject. High school baseball caps a career at three years by rule, so players disappear no matter what the user does. The developer did not design the deadline; the material arrived with one. Furuta advises other developers to take a classic game such as baseball, shogi or othello and add original elements to it. Frankly, what worked here was less the classic format than the fact that this particular classic replaces its cast every single year. The scouting ticket, which improves the quality of incoming first-years, obeys the same calendar: it only means anything in the enrollment window.

A revenue curve that spikes in August

Dividing ¥12.9 million by eleven months gives an average near ¥1.17 million, which makes the ¥2.57 million peak 2.2 times the average. The previous title showed the same shape, rising during summer vacation and the tournament season to a peak of ¥400,000. The calendar sets the shape of revenue before any tactic does.

Acquisition was tuned to the same calendar. Putting the word Koshien into the subtitle lifted the app into search results it had never appeared in, and Furuta kept a record of which keyword settings paid off. Review prompts appear only after a player wins a match for the first time, which collected 2,500 reviews on Google Play. The App Store listing shows the game still live as of September 2026, free with in-app purchases, rated 4.6 across 35,000 ratings, with a description stating that there is no operations team because one person builds it.

One video of stamina, and 50 gems for a bug report

The advertising side was fitted to the same resource design. Adding an option to restore stamina by watching a video after a win doubled rewarded-video revenue per download. Stamina is a finite resource that training consumes, and it does not compete head-on with the paid items. Furuta has written that banner ads pay a few tens of yen per click at a click rate near 1%. Building 24% of revenue at that price means giving people a reason to watch.

For retention, he watched player behavior, found that the overwhelming majority closed the app right after losing a match, and began granting a training-efficiency bonus after defeats. It is a plain fix: put the next reason where people stop. Early in development the app carried a line saying you might get a thank-you for reporting bugs, and reporters received about 50 gems, worth roughly ¥50. Reports arrived with reproduction steps and screenshots, to the point that he wondered whether the sender was a professional tester. Fifty yen hired an outside QA team.

The prior title made ¥3M, and before that he was burning savings

This ¥12.9 million sits on top of a count of failures. The earlier title, Let’s Build a Sandlot Baseball Team: Legend, launched in March 2016 and had earned about ¥3 million by September 2017, split ¥1.5 million in purchases and ¥1.4 million in ads, with a peak month of ¥400,000 and server costs of ¥1,000 a month. Counting from the first sandlot game, the third attempt was the one that cleared ¥1 million a month. The first year or two after going independent ate his savings, and several early apps failed. Before this project he abandoned a tennis game at 50% completion, and an escape game released in 2017 reached tens of thousands of downloads without giving anyone a reason to keep playing after the ending. His description of that period: starting something new feels like throwing a pebble into a large lake, where nothing happens.

Plenty stays invisible. The labor he charged himself for six months of development, any ad spend, the iOS and Android revenue split, and the trajectory after October 2018 are not public. The ¥12.9 million is gross revenue before store fees, not take-home pay. The figures also come from an interview, reported by App Marketing Institute from his own account, with no third-party verification.

How far this carries

Among solo-built phone apps, this site covers iStalk, a conversation-analysis app that reached ¥2.5M a month through TikTok traffic, a developer running three apps in parallel for ¥200,000 a month, and an app that settled at ¥50,000 a month in ad revenue five years after launch. The ¥2.57 million peak here tops that list, and it is also a number that arrives one month a year.

• Charging for the avoidance of loss works only when the play itself already contains an expiry, and carrying something past that expiry does not break progression
• A month at twice the annual average appears only when the subject has a fixture that lands in the same month every year, and that fixture’s name can be made searchable in the store
• Rewarded video doubles revenue only when the reward is a finite resource like stamina and does not eat into paid item sales

The limits deserve their own line. These numbers belong to someone who set himself a one-year ultimatum and built a third title on the users and systems of a second one. He also had local advantage, having found an art student at a Nagoya university festival to handle the previous game’s design. And 2018 was still a period when individual apps grew on ads and store search, unlike the record of ten apps over eight years falling to ¥30,000 a month that we cover elsewhere, where the same playbook stopped paying.