The answer for Japan could be summarized by two points.

First, there was no unified code of Bushido until the Meiji period.

Second, here's what jesuit Luis Frois said about the so-called Japanese "honour":

Among us, treason is rare and is considered highly reprehensible; in Japan, it is so common it that it is almost never considered reprehensible.

See also here, here, here, and here.