A kind of like adding up all posts here denying Chinese culture one must arrive at the conclusion that China did not exist.
Therefore, logically speaking this type of denial must be heavily flawed. It just takes an unfair amount of patience to handle it.
However, as I already said, what we can learn from the US is to put a military base there. Once this is done, Japan will be as responsible with its past as it is cooperative with the US today. Of course, we can't put a military base there but something of parallel effect can be done. The idea is clear.
In reality Japan looks very bad for all its neighbors hate it after WW2, somewhat like Israel. Not a truly wise nation.