The 27-year-old Yamaguchi parades an impressive 14-0-1 win-loss-draw record with 10 wins by knockout.
The Japanese, however, hasn’t fought against tough foes unlike Santillan, who had clashed and knocked out top Japan contenders in the likes of Hiroshi Watanabe, Kazuhiko Hidaka, and Daigoro Yamamoto.
Santillan and Yamaguchi have one thing in common, they both have had fought Korean Yong Hwa Choi.
The WBC ranked No.1 147-pounder Santillan floored Choi in the fourth round, while Yamaguchi won by decision over the Korean, giving the Filipino champion an edge power-wise.
Santillan, sporting a 22-2-1 win-loss-draw ledger spiked with 16KOs, is making his first defense since he regained the OPBF throne he lost twice by decking Japanese Kazuhiko Hidaka in the eighth round during his last fight on Dec. 3 last year also at the Korakuen Hall.
Expected to cheer for Santillan at the ringside are his manager, noted Cebu boxing promoter Rex "Wakee" Salud, and trainer Brix Flores.