Most free mahjong games deal unwinnable boards. I built mine backwards.

Mahjong solitaire is a matching game where players remove pairs of identical tiles from a 144-tile pile, provided the tiles are free with no top stack and at least one long side open. However, the conventional way of dealing these boards routinely leads to dead ends.

The straightforward method of shuffling all 144 tiles and dropping them onto a layout is flawed. A random arrangement easily creates unwinnable states where the final four tiles are buried under each other or a pair is locked permanently. Players usually discover this twenty minutes into a game when no matches remain.

The remedy is to stop generating boards and checking them afterward, and instead generate a complete solution first and derive the board from it. Playing back that removal order guarantees that a valid solution exists before the player ever touches a tile.

A fallback mechanism is in place if all sixty generation attempts fail, pairing adjacent positions to produce a functional board even if solvability isn't strictly guaranteed. This branch has never been triggered, but the developer kept it to ensure users see a game screen rather than a blank page.

Regarding tile faces, the Unicode mahjong block (U+1F000–U+1F02B) is frequently broken or missing in default Windows and Android font stacks, which would render the game unplayable. Consequently, the tile faces are rendered using SVG graphics.

Public-domain riichi mahjong artwork covers 33 out of 42 faces, but lacks flower tiles, season tiles, and the white dragon. To fill the gap, the missing outlines were extracted directly from the Noto Sans Symbols 2 font using fontTools.