Authentic Kashi wood Bokkens are still used today, but are becoming quite costly. They also have the disadvantages, being made of wood, that they may rot, crack split or splinter. Cold Steel’s solution to these dilemmas was to design a synthetic substitute, low in price and impervious to the elements.Our Bokken and our new Wakazashi Bokken are made of the heaviest grade polypropylene available and closely duplicate a real Katana and Wakazashi in length, size, weight and feel. While they’re not quite as rigid as wood, they have the advantages of being virtually unbreakable and remarkably stiff and cut resistant.