Tossa no Keisan Shunkan Kaitou: Keisan DS Training

Tossa no Keisan Shunkan Kaitou: Keisan DS Training is a Japanese educational Nintendo DS game released in 2007, focusing on mental math (keisan) with quick calculations (shunkan kaitou), designed to train users' math skills and is region-free for play on any DS console.

This game challenges players to perform rapid mental arithmetic problems, improving their calculation speed and accuracy. It's part of a series of Japanese math training games for the DS, offering a fun way to practice math.