Thirty-One is made and published by Koichi Iwasaki. AppBrain is an independent app data site and isn't affiliated with Koichi Iwasaki. The app name, icon, screenshots and description belong to Koichi Iwasaki and are shown as published on the App Store.
AppBrain's verdict
- Last updated
- February 20, 2026
- Size
- 100.8 MB
User feedback
Ratings and reviews on the App StoreComments on Thirty-One for iOS
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Store listing
By Koichi Iwasaki, from the App Store
Description by Koichi Iwasaki Written by the developer, not by AppBrain. Click to read.
◆ Face off against unique rivals! Challenge nine distinct characters, each with their own playstyle:
Newbie: A beginner whose unpredictable moves might surprise you.
Aggressor: A bold player who loves to ”Knock” early.
Tactician: A strategist who calculates maximum efficiency.
Stoic: A steady player who prioritizes not losing above all else.
CPU Master: The ultimate AI that calculates every probability.
◆ Customize the rules your way! Fine-tune the game settings to match your favorite playstyle:
Should Aces (A) count as 11 points?
Should Three-of-a-Kind count as 30.5 points?
Will you allow ”Blitz” or ”Sweep”?
Use your best strategy to defeat the ultimate CPU Master!"
Safety and technology
Found in the app by AppBrain- Price
- Free
- App size
- 100.8 MB
- Content rating
- Everyone
Technologies used by Thirty-One
Releases
Updates seen on the App Store- Version
- 1.0.1
- Launched
- December 2025
No changelog data
Alternatives
Similar apps and more from Koichi Iwasaki
Rankings
App Store top chartsApp Store Rankings for Thirty-One
About the app and developer
About Thirty-One
Thirty-One is a games app developed by Koichi Iwasaki.
User Ratings
The app has no ratings yet.
App Information
Thirty-One is freely available from the App Store. The app size is 100.80 MB. The latest version available is 1.0.1. The last update was on February 20, 2026.
Technical Requirements
The app has a content rating of Everyone. The app has been available on the App Store since December 2025.
Developer information for Koichi Iwasaki
Address:
Frequently asked questions about Thirty-One
Is Thirty-One free?
Yes. Thirty-One is free on the App Store.
Is Thirty-One still available?
Yes. Thirty-One is on the App Store, and the last update we saw was on February 20, 2026.
How large is Thirty-One?
Thirty-One is 100.80 MB.
Is Thirty-One suitable for children?
App Store rates the content of Thirty-One as suitable for everyone.
Who made Thirty-One?
Thirty-One was developed by Koichi Iwasaki. It is listed in the games category on the App Store.
What are the best alternatives to Thirty-One?
People looking at Thirty-One also look at these games apps: Easthaven Solitaire FeinGames, ゆるキャン△かるた, Spades+, Crazy Eights Classic Card Game, Spades Royale: Online + Single.