Baketsu Daisakusen is a cancelled horse-racing RPG / simulation in development around 2001 by Nintendo for their Game Boy Advance. As other horse-racing game popular in Japan you could play it as a racing game or as a simulation in which you just bet on the results, while the game internal AI would predict which horse would win the race based on their stats and previous 5 runs. It seems Baketsu Daisakusen would also let you play online against other players, using the GBA’s cell-phone adapter.
In the end, Nintendo never released the game for unknown reasons. Only a few, tiny screenshots still exist today to remember its existence.