This is an interesting game recently played on KGS by two kyu players. The upper-left corner is a bend-four, which by definition in Japanese rule is dead. However, there is a seki around *bs*, which means if they were to play on (under a different rule set), white would not be able to kill the corner without losing the group forming the seki. The position on the board was that white would win if the corner is ruled to be dead. And black would win if they were to play on. Making things even more interesting (but technically not relevant to the argument) is a second seki around *bx*.
I am no rule expert so I cannot comment any more than what I've done.