Does a shinai blow hurt?
A correct shinai blow which lands on target, ie on the armour, doesn’t hurt. You know you’ve been hit, but there is no pain. A heavy handed cut driven by too much muscle, a typical beginner’s stroke, can hurt a bit, more so if the armour is old and soft. The shinai itself is designed to flex and absorb the blow. A cut which misses the armour causes no worse than a bruise, although it certainly can hurt at the time.