Hearts heal in Tokyo, one a turn
A monster in Tokyo may heal one health for a heart rolled, once per turn, instead of the hearts doing nothing at all. Everything else about Tokyo is unchanged — you still leave only when an attack lets you, and you still take everyone's attacks. The printed rule voids hearts entirely while you hold Tokyo, which at two players grinds both monsters toward zero: whoever holds it cannot repair, and stepping out means handing the other player the throne and the points.
