Honyaki (literally "true-forged") knives represent the highest level of craftsmanship; only a few skilled craftsmen in Japan can make them. These craftsmen employ techniques similar to that of traditional nihonto (Japanese sword) where a single piece of steel is differentially heat-treated.
Making honyaki knives is a challenging and time-consuming process as it involves a high degree of skill in temperature control and forging. Failure rate is quite high---some blades will crack or will severely warp in the quenching process. The additional labor in sharpening and finishing also contributes to high prices.