PRO YAKYUU GREATEST NINE '98 SUMMER ACTION CHEAT CODES
None.
PRO YAKYUU GREATEST NINE '98 SUMMER ACTION TIPS & TRICKS
None.
PRO YAKYUU GREATEST NINE '98 SUMMER ACTION UNLOCKABLES
Night Home Run Derby
Hold Start at the home run mode selection screen until the home run derby begins.
Rainy Weather
Hold Y + L + R and press Start at the opening mode selection screen.