Learn how to transform your boxer briefs into a blade with the help of traditional knifemaking techniques.

While some of us have hobbies, others of us have obsessions, and Japanese YouTuber and knife craftsman Attoteki Fushinsha no Kiwami appears to fall into the latter category, with his unending stream of handmade knives crafted from some of the most unlikely materials.

His handiwork is truly impressive, and despite all the hard work and elbow grease that goes into each of his handcrafted projects, it appears that no material is too difficult for him to master. Whether it be aluminium foil, pasta or even jelly, Attoteki Fushinsha no Kiwami knows how to turn just about anything into a blade, and now he’s back with an even more astounding transformation involving underwear.

Watch below as a few pairs of boxer briefs become a knife sharp enough to chop up your dinner ingredients.

At the beginning of the clip, the knifemaking process starts by unwrapping the materials for the new knife: underwear made from 100-percent cotton, and underwear made from a 92-percent nylon and 8-percent polyurethane blend.

Using five pairs of boxer briefs in total, he gets to work by cutting them up into pieces, which are then ironed to create flat, crease-free materials. These are then taken over to the stovetop, where a heavy cast iron pan is heated up to roughly 300 degrees Celsius (571 degrees Farenheit) and then pressed onto the cloth.

While the nylon-polyurethane material binds together and becomes hard when heated, the all-cotton material remains pliable, so the two types are folded together and heated, layer upon layer, until the ideal thickness and firmness is created.

After the layering and heating is complete, the material becomes surprisingly hard. That’s when it’s time to trace the outline of a knife onto the fabric before cutting it into shape. Once that’s done, the knife is heated again and then laid between two boards under the weight of a couple of bricks.

After the knife has been shaped and hardened, it’s onto the process of sanding the surface and edges, using different grades of sandpaper until it’s perfectly smooth. The next step is to sharpen the blade using whetstones to give it a sharp edge. After all that elbow grease is over, the blade looks like this.

The edge has been sharpened so beautifully that it ends up looking like a real metallic blade. The use of colourful, patterned underwear helps to create graduated colour at the edge, to make it look like sharpened steel.

The only thing left to do is test the blade in a kitchen environment, and the video shows that it’s able to slice through raw chicken, paper, cucumber and tomato. So how does the underwear knife stack up compared to the other non-metallic knives in his repertoire?

It sits in eighth place, just below the knife made from plastic bottles and above the plastic wrap knife, which is currently in ninth place. Having made more than a dozen knives so far, Attoteki Fushinsha no Kiwami continues to hone his skills with each new masterpiece, so we can’t wait to see what he comes up with next!