Kombu and katsuobushi stock — the umami floor of Japanese cooking. Cold-steep at 60°C, then heat-pull at 70°C, strain.
Edo period, 1700s — Osaka merchants industrialized the trade of Hokkaido kombu down the Kitamae-bune sea route. Katsuobushi (smoked-fermented skipjack) production at Yaizu and Makurazaki paired with kombu to set the modern ichiban-dashi formula by mid-Edo.
The 7-8x synergy was quantified by Ikeda Kikunae's student Kuninaka Akira at Yamasa in 1960 (Nature paper). Yoshihiro Murata of Kikunoi (Kyoto, 3-Michelin-star) makes ichiban dashi in 90 seconds at 65°C — anything longer is wasted leaf, he says.
Pale gold to amber liquid, surface-still, no fat. Aroma is sea-breeze and toasted bonito; taste is glutamate-inosinate umami synergy that hits before salt registers. Drunk hot, plain, it tastes like dawn ocean.
Kombu releases L-glutamate at 60°C — boil it and you get bitter alginate. Katsuobushi releases inosinate at 80°C — simmer it and you get fishy. Hold each at its sweet spot, then strain immediately. The 7-8x umami synergy between the two acids is the load-bearing trick.
Variations
Ichiban dashi (一番, first extraction, 5 min, for clear soups), niban dashi (二番, second pull from spent leaves, for braising), niboji dashi (sardine-based, Kansai home cook), shojin dashi (vegan, kombu + shiitake, Buddhist temples like Daitoku-ji).
On the Palate
Where Dashi sits in the Japanese flavor cloud
Ingredients
Serves 6How it's made
4 steps · 2 min active + 1 hour 31 min waiting
- 12 min
Wipe 30 g dashi kombu with damp cloth (do not rinse).
- 230 min
Soak kombu in 1 L cold water 30 min; gently heat to 60 °C.
Watch outBring the kombu up slowly and never let it boil — past 60 degrees it turns bitter and slimy instead of sweet.
- 360 min
Hold at 60 °C 1 hr; remove kombu just before water reaches 80 °C.
Watch outLift the kombu out just as fine bubbles start to rise from the bottom — that's the cue you're near 80 degrees.
- 41 min
Add 30 g katsuobushi; let infuse 30 sec; immediately strain through fine cloth.
Watch outSteep the katsuobushi only about 30 seconds, then strain at once — linger and the broth turns fishy.
