Regardless of whether or not Japanese men use a full year of paternity leave, it should continue to be an option for them. For those whose wives need additional aid in raising a newborn child, it would be comforting to have the option to take leave to help with child-raising without the accompanying economic burden.
It doesn't matter what percentage of men use it; they should still be given the option. If they use it, that is their right. If they don't use it, then that benefits the company. Offering paid leave that goes unused doesn't cost the company anything. The real question is "Should Japanese men use more of their paid paternity leave?" The answer, in my opinion, is yes.
I don't see a reason to get rid of paid paternity leave for men in Japan just because most of them don't use it. Since they currently have it available, I don't think they should get rid for it for those who do want. Plus, since most men don't use it, it is great public relations for the country at a low cost!
Men in Japan should not receive a full year of paid paternity leave. It is not necessary most of the time. There are instances in which the child may need more care than the mother alone can provide, but that is not the norm. Six months would be plenty. They should have the option as to if they will utilize it of course, but I do believe they should have it a leave period. As a mother, I know that those first few months can be difficult dealing with a newborn. This will allow mom to get rest when needed which, in turn can cut down on the stress and fatigue that most new moms experience. It also allows dad to bond with baby and establish a relationship with the child early on. However, it must be kept in mind that the job they are on leave from still needs to be done so the company is left with a need to fill that position. They should not be obligated to pay you not to work for a year.