I stand by my theory that Ayumu is actually a pair of twins, sharing a life due to a clerical error during their birth. One loves Rin and kendo, and the other loves Urushi and shogi. Shogi/Urushi Ayumu must play on kendo/Rin Ayumu's level during matches, or their secret will be revealed. This is the real conflict of the story: A fateful rock paper scissors match decided on Urushi route, but the Rin stan twin doesn't fully commit. Thus we have this flip-flopping scenario where Rin must suffer the ambiguity.