Katsuobushi (Bonito Flakes)

Katsuobushi are paper-thin shavings of dried, fermented and smoked skipjack tuna, and the more elaborate process behind them rivals fine cheesemaking. Whole fillets are simmered, smoked over wood for weeks, then deliberately inoculated with a mould that draws out remaining moisture; the resulting block is hard as wood and shaved to order with a special plane. Beyond their role in dashi, the flakes are a flavour weapon: scattered raw on top of hot food, they 'dance' as the steam moves them and release deep umami and a faint smoky-sweetness. They keep a long time sealed but oxidise once opened, so use within a few months.