Hiro's company built the stadium so the staffs could get free tickets to watch the game there. Hiro said that he wanted to show Iki a lot of new things he could see in japan while we're here for -only-God-knows-for-how-long.
I've never been watching baseball before in my life (not even on TV!) so I actually didn't understand at all how the game worked, but I enjoyed being in a big stadium with the enthusiast supporters. I could feel their energy as they shout, sang, and danced the best they could to support their team.
Even Iki who said that he didn't understand the game at all started to wave the flag, shouted "JOUJIMA" (which I dont understand :p) and moved his body in the same rhythm with the supporters LOL
I guess we enjoyed our first experience watching baseball ;-)