The fourth installment of Keisuke Itagaki's Baki manga, the manga takes place after Baki's epic confrontation against his father. Baki continues to fight and train nonstop, but he always has to suppress his yawn caused by the overbearing boredom. But this changes thanks to plans of cloning Miyamoto Musashi, one of the fathers of Japanese martial arts. Another fight of historical proportions awaits Baki.
[Source: Anime News Network, Baki Wiki (plot summary)]