Though I'm loathe to check in bags--partly because you never know if it gets loaded during a tight connection--I wonder whether the ground crew at IAH will be pretty reliable when it comes to a connection time for an international flight that leaves roughly 2 hours later.
In other words, do you think that I'll be ok with checking in a bag and knowing that it will make it to Tokyo with me? I guess I could always just ask the BF concierge...