Taiji Challenge is a free puzzle game developed by Soft Cyd for Android devices. It is similar to Sudoku but requires filling a grid with 0 or 1 according to three rules. The rules are: no more than two 0 or two 1 in a row or column, as many 0 as 1 in a row or column, and no two identical rows or columns.

This game offers over 2000 grids of varying difficulty levels for both smartphones and tablets. The grids range from 4x4, 6x6, 8x8, and 10x10 for smartphones to 12x12 and 14x14 for tablets.

Taiji Challenge is a great choice for those who enjoy Sudoku and other similar puzzle games. If you encounter any issues while playing or have any questions, the developer can be reached through email. Additionally, Soft Cyd is looking for translators for the game.

Overall, Taiji Challenge is a fun and challenging puzzle game that is worth checking out for fans of the genre.