>>530476295
the reason kitasan black is used is her specialty bonus at MLB is +100% so you can reliably spam nothing but Speed trainings and get friendship bonuses and cap Speed rating on basically any horse.

At 3* she drops down to 60% specialty which is still good but even welfare Special Week has 30%. Below 3* she has only 20% specialty bonus and none of her skills are must-haves, especially if you already have the other goodstuff.deck options like Super Creek and Fine Motion (and several are redundant with special week welfare as well)

actually look at the mechanics of why something is used rather than blindly follow tier lists