It means "ichiban" of "ichiban yoi"(= mottomo yoi), it's "the best". In this case, this sentence wants to say "the combination is the best", "mutch the best". Other examples: I like coffee the most. --> Watashi ha kōhī ga ichiban suki desu. the best way --> ichiban yoi houhou the kinesest teacher --> ichiban yasashii sensei You can say these "ichiban" --> "mottomo" I hope that I could explain well with my English and that this was helpful.