Man, Ichikawa is clueless. As were were we all around that age. Even though it's clear to us and should be clear to him at this point, that Yamada like him. Considering that they held hands on more than one occasion. The first time could have been written off in his mind because of the circumstance of needing to stay together on a crowded train. Although, why would she keep his hand after? hmmmm
The second instance however, should have clued in the little guy. Yamada set him up, took his hand, and didn't give it back for some time.
I'm super interested to see how this relationship blossoms. I wonder if they'll leave things unspoken for some time more.