About This Game

Unlock Cosplay Costumes by Battling Girls in an Original Mahjong-Inspired Game!

San-Yon: Third Daughter? Four Tiles! is a mahjong-style board game where you engage in one-on-one matches against three girls, each with a unique playstyle. Win a match, and you'll unlock a special cosplay outfit for your opponent.

The game is played using "Four Tiles (Yontui)", a simplified version of mahjong created specifically for this title. There’s no need to memorize complex hands or calculate scores. Even players with no prior experience in mahjong can enjoy the game through its easy-to-understand, intuitive mechanics.

What is Four Tiles?

Four Tiles is a two-player-only, original mahjong variant. Your goal is to form four "tiles" (sets) before your opponent does, in order to score points.
A "tile" refers to a set of three matching tiles — either three sequential numbers or three identical numbers or symbols.
The game retains the strategic depth of traditional mahjong while streamlining the rules for accessible gameplay.

Unlock Cosplay Costumes

By defeating each girl, you’ll unlock a unique cosplay costume for her.
Each character has her own themed outfits, which can be viewed anytime in the gallery after unlocking.
Collect them all to complete your cosplay gallery!

Her Secret

Regardless of the match outcome, completing a match reveals a piece of each girl's secret story.
Uncover the hidden side of each character as you progress through your matches.

AI Generated Content Disclosure

The developers describe how their game uses AI Generated Content like this:

This game uses generative AI for creating parts of the programming code.

Mature Content Description

The developers describe the content like this:

The game features a system similar to undressing Mahjong, but instead of nudity, the losing character changes into various cosplay costumes. There are no depictions of sexual acts, genitalia, or non-consensual content. The content is lighthearted and comedic in tone, and the game is intended for mature audiences.