All you need is the Mano (no forces) at Lv4 - Lv10, the improved catcher, and access to the town in Rest Hamlet.

• Step 1: Enter the town(preferably at day) and go all the way up until you hit a closed door.
• Step 2: Shoot this door with any weapon other than the Mano or catcher.
• Step 3: Switch to the Mano then enter. You should see an enemy called Fat Man(fire).
• Step 4: Attack him with the Mano until he dies. Write down the number of times you hit him with the Mano.
• Step 5: Leave, Recharge both weapons, then re-enter.
• Step 6: Hit the Fat Man with the Mano but hit him one less time than it took you to kill the last guy. Then fire the catcher until you catch him. Do the same to the Fat man on the right.
• Step 7: Leave, then repeat from Step 5 until you have low health or more than 65 Fat Men caught. When you do, leave town and got to the Master's house. Evolve all your weapons EXCEPT THE MANO.
• Step 8: Sleep to refill your health, save then repeat from Step 2.

The reason you have to repeat from Step 2 instead of Step 6 is because there is a very large chance the Mano became stronger. If at any point the Mano 1-hit KOs the Fat Man you can still do the trick but with another weapon.