The Japanese southpaw is expected to defend his title for the eighth time at Osaka’s Bodymaker Colosseum when he gets in the ring with the undefeated challenger (23-0, 15 knockouts).
Yamaka said: "My balance has been good in training. My opponent has an opening before and after he throws punches. If I strike, then I'll naturally get a KO."
Yamaka won the title in 2011, and has thus far defended it against all comers. However, Santillan will be a tough fight as he is five years younger and has an excellent record.
Just yesterday Yamaka was linked with a fight against Cuban star Guillermo Rigondeaux, however in order to secure that fight he would most likely have to go up in weight.