Much like every other yakuza game, you can pick up weapons off the floor in the middle of a battle and they will have durability. Basically, just keep using it on enemies until the weapon breaks. This achievement was made a lot less grindy than it was on the original ps3 version which was to break 100 weapons. Easiest weapons to break or stuff like traffic cones and shop flags which will usually have a durability of 3-5 hits before it breaks.