Mission 2 - Nakasendo Road: do not rotate the map, so you can see the locations on the starting view (just to memorize them). Also take care with other guards around the spots, making some "cleaning" if needed to not be detected or raise an alarm.
1- Kill a guard using an ox: on the bridge (center of the map) with the carts on it, just climb the rocks and go to the spot just above the oxe with a guard behind him, at the left riverbank just beside the bridge. Throw a rock on the ox, and it is done (actually you can kill more guards as they go there to investigate);
2- On the bottom left side of the map (SW), where the road takes a sharp turn, there is a boulder on the edge of a cliff. Use it (pressing A on it) to crush the guard that is patrolling the road, just as he passes bellow it;
3- On the upper left (NW) side of the map, crossing the river, there is a wagon on a slope, with blocks on the wheels holding it, and a guard just bellow it. Just wait the patrolling guard to chat with the stationary one and proceed to move both blocks from the wheels to make the wagon crush them (using A on the blocks);