In our last issue, we looked at why installs are a trap in Japan.
Hypercasual campaigns generating 20% of all installs in Japan produce just 1% of all sessions. Users downloaded the game, opened it once — or not at all — and disappeared. You paid for the install. Japan didn’t pay you back with a player.
So the question has to change.
What exactly are you paying for?
The real value starts after the install
Traditional UA charges at the moment of install. CPI — Cost Per Install. The moment a user downloads your app, the budget moves.
But if that user never plays, what did you actually buy?
Not a player. A number.
In Japan, real value is generated after the install. Users open the game, play it, consume content, and spend. Japan’s iOS users average $10.3 in monthly mobile game spend — the highest in the world.
That spend comes from users who played. Not users who installed.
(Source: Adjust / data.ai, 2025)
CPE: Paying for behavior, not presence
This is where CPE (Cost Per Engagement) comes in.
Instead of paying at install, advertisers pay when a user completes a defined in-game action — reaching a level, completing the tutorial, making a first purchase. The billing event is tied to behavior, not presence.
The difference this creates is straightforward.
CPI buys installs.
CPE buys behavior.
A user who completed a behavior has, at minimum, experienced your game.
What the data says
From a 2025 survey of 502 mobile game developers across the US and UK:
(Source: Almedia — Rewarded Returns Whitepaper, January 2025)
CPE isn’t just a better ad format. It changes the measurement framework entirely. Instead of install volume, you’re tracking event completion rates. Instead of D7 ROAS, you’re reading D30 to D90 retention. Instead of cost-per-install, you’re measuring cost-per-event against revenue-per-event.
Why CPE works especially well in Japan
Japan has a cultural infrastructure that makes this structure uniquely effective.
Poikatsu (ポイ活) — the daily habit of earning and accumulating reward points — is practiced by 81.3% of Japanese consumers.
(Source: Cross Marketing, 2025)
Japanese users are already conditioned to the logic of “complete an action, receive a reward.” On point sites, they share information about which campaigns offer the highest payouts. They research completion guides before participating. Engaging with reward campaigns is already a normalized daily behavior.
When these users enter a CPE campaign, they’re not just chasing a payout. In the process of completing the milestone, they experience the game, consume its content, and some become genuine players.
Users acquired through reward campaigns spend an average of 326% more than standard UA users — with some cases reaching 500%.
(Source: MAF.ad / Unity, 2025)
The shift already happening in Japan UA
The question “how many installs did we get?” is already outdated in Japan.
The teams moving ahead in this market are asking one question instead:
“What did those users actually do?”
Paying for the answer to that question. That’s where Japan mobile UA is going. 🎯
Ready to shift from installs to behavior?
If you’re planning a CPE campaign in Japan or have questions about your current UA strategy, Rocket A is here to help.
Visit us at rocket-a.com to request a meeting — we’re ready to talk through your campaign goals and find the right approach for your game in Japan.
👉 rocket-a.com
References:
1. Adjust & data.ai (2025). The Mobile Gaming Market Report
URL: https://gamedevreports.substack.com/p/adjust-and-dataai-the-mobile-gaming
2. adjoe (2025). APAC Mobile Gaming Guide.
URL: https://adjoe.io/blog/guide-advertising-mobile-games-across-apac/
3. Almedia (2025년 1월). Rewarded Returns.
URL: https://almedia.co/press
4. Cross Marketing (2025). Poikatsu Survey Report.
URL: https://www.cross-m.co.jp
5. MAF.ad / Unity (2025). (URL Not available)
