Katsuobushi Shaving Kezuri-bako Box Technique

Japan; katsuobushi production centers Makurazaki (Kagoshima) and Yaizu (Shizuoka); kezuri-bako traditional household tool

Freshly shaved katsuobushi (dried fermented bonito) represents the highest quality form of this essential Japanese ingredient, and the kezuri-bako (bonito shaving box) is a traditional tool that allows households and restaurants to produce paper-thin shavings from a whole dried bonito block on demand. The traditional kezuri-bako resembles an inverted wooden box with a steel plane blade set at a specific angle near the front. The dried katsuobushi block (honkarebushi, the premium fermented and molded form) is drawn across the blade in long strokes, producing translucent, paper-thin shavings that collect in a drawer beneath. Freshly shaved katsuobushi has dramatically superior flavor compared to pre-packaged thin shavings (hana katsuo)—more nuanced, less harsh, with greater aromatic complexity from preserved volatile compounds. The shavings also flutter beautifully in steam and over hot surfaces (as seen on takoyaki and okonomiyaki). The block darkens with oxidation on the cut surface, so the surface should be shaved clean before using. The fermented mold (Aspergillus glaucus) used in honkarebushi fermentation contributes enzymes that create the extraordinary depth of the finished product through protein breakdown.

Smoke, fermented depth, oceanic umami; fresh shavings more aromatic and nuanced than packaged; subtly sweet