Knowing how much was deliberately copied versus transmitted unintentionally through cultural osmosis can be a hard thing to determine, in some cases though it's pretty obvious. Take, for example, one of Hideo Kojima's first games - Snatcher.
In some ways the resemblance is a no-brainer since the first Way of the Samurai game takes place in a similarly isolated Japanese village during the Meiji restoration. Hence, it makes sense that similar clothing, hair as well as notions of the ending of one era and the beginning of another, dominate the narrative. However the similarities extend even further to plot elements; assimilation by a ruthlessly militaristic government official, a blood-thirsty killer who actually isn't all that bad, not to mention an ending that involves copious amounts of fire and bloodshed. There's even a damsel in distress. It's all a bit odd considering that "Yurusuzaru Mono" is supposed to be borrowing plot points from "Unforgiven," and yet aside from the basic outline the resemblance between the two films feels inconsequential compared to Way of the Samurai. Did the director of "Yurusuzaru Momo" play this old PS2 game during his formative years? I don't know, but if he didn't that's one heck of a coincidence.