How much the age gap between them?

around 7 or 8 years i think. bcos Yamasake was 15 when he met Hatakeyama when he just graduated from university.

hmmm Hatakeyama is 33 and they say its been 10 years, so he was 23 when Yamasaki was 15 so it would be an 8 year gap, though it seems smaller when they showed them as kids