Japanese Shottsuru and Ishiru: Regional Fish Sauce Traditions of Akita and Ishikawa

Overview

Japan possesses its own indigenous fish sauce traditions predating Southeast Asian influence — regional condiments produced by fermenting whole small fish in salt that are among Japan's most distinctive and least-known fermented ingredients internationally. Shottsuru from Akita and ishiru from the Noto Peninsula of Ishikawa Prefecture represent two approaches to the same principle: protein enzymatic hydrolysis under salt producing amino-acid-rich, pungent liquid condiments with extraordinary umami depth. Shottsuru (from 'shottsu', the local name for sandfish — hatahata in standard Japanese) is made from sandfish (Arctoscopus japonicus), an Akita speciality that spawns in large numbers on Akita's Sea of Japan coast from November to December. Fresh sandfish are layered with salt at 30-40% salt ratio in wooden barrels and left to ferment for 1-3 years. The high-salt, cold-climate fermentation produces a pale amber, clean fish sauce with subtle, clean flavour character — less pungent than Southeast Asian fish sauces due to sandfish's white flesh. Shottsuru is most famously used in Akita's kiritanpo nabe hot pot, where it seasons the dashi together with soy sauce and mirin, but it functions as a universal umami seasoning for any application. Ishiru (or ishiri) from Ishikawa Prefecture is produced from the offal (primarily viscera) of squid (surume ika) or the whole small fish (iwashi sardine), producing a darker, more robustly flavoured sauce than shottsuru. The Noto Peninsula's coastal fishing culture and traditional preservation methods have maintained ishiru production through centuries of local use. Both sauces represent the third pillar of Japan's umami triumvirate (alongside shoyu and miso) in their respective regional cuisines. The historical depth of Japanese fish sauce tradition extends further: archaeologists have found evidence of gyosho (fermented fish pastes) in Nara Period sites, suggesting fish sauce traditions predating the development of both shoyu and miso in Japan. Understanding these regional sauces contextualises the global history of fermented fish condiments and positions Japanese umami culture within the broader fermentation tradition.

Flavour Context

Shottsuru: clean, delicate, transparent umami with subtle marine notes; ishiru: more robust, pungent, complex depth — both function as background umami amplifiers rather than dominant flavour elements

Key Principles

{"Shottsuru uses whole sandfish (hatahata) — the white flesh and clean fat profile of sandfish produces a notably clean, subtly flavoured sauce compared to oily fish equivalents","Ishiru uses squid viscera or sardine — the darker raw material produces more intensely pungent, complex flavour with distinct iodine and umami depth","High salt ratios (30-40%) and cold northern climate (Akita winters) create slow, clean fermentation without off-notes from warm-climate lactic fermentation","Both sauces function as direct substitutes for any fish sauce application while bringing specifically Japanese flavour character — particularly effective in dashi-based preparations","The historical precedence of Japanese gyosho (fish paste/sauce) traditions suggests shoyu and miso were in part shaped by existing fish fermentation knowledge","Regional identity is inseparable from these products: shottsuru is Akita, ishiru is Noto — their use signals regional affiliation in traditional cooking","Unlike Southeast Asian fish sauces, Japanese fish sauces have limited international distribution — authentic products require specialist sourcing from Japanese importers or direct from producers"}

Pro Tips

{"Add a teaspoon of shottsuru to any dashi-based preparation — its amino acid profile synergises with kombu glutamates and katsuobushi inosinate to create a third-dimensional umami that pure shoyu cannot match","Kiritanpo nabe (Akita's autumn/winter hot pot with rice cylinders, chicken, and root vegetables) is the canonical shottsuru application — even small additions of authentic Akita shottsuru transform the preparation","Ishiru's stronger profile makes it excellent in applications where the fish sauce character should be more prominent: as a direct dressing element for grilled squid or octopus, or in strong-flavoured braises","A blend of shottsuru and shoyu (1:4 ratio) produces a complex, layered seasoning for light-coloured soups and clam broth preparations where all-shoyu would be too direct","For programs covering Japanese fermentation culture, presenting shottsuru and ishiru alongside garum (European fermented fish sauce revival) demonstrates the deep historical universality of fish fermentation across cultures"}

Common Mistakes

{"Substituting Thai nam pla or Vietnamese nuoc cham for shottsuru and expecting equivalent flavour — Japanese fish sauces are notably cleaner and less pungent due to different fish, climate, and fermentation conditions","Overusing fish sauce as a direct flavour element rather than as a background umami amplifier — like shoyu, a small amount transforms a preparation without announcing itself as 'fishy'","Heating fish sauce at high temperatures for extended periods — this produces bitter, harsh compounds; add fish sauce late in cooking or off heat","Treating regional Japanese fish sauces as interchangeable — shottsuru's white-fish delicacy and ishiru's squid-viscera intensity are meaningfully different and suit different applications","Assuming fish sauce traditions are exclusively Southeast Asian — Japanese gyosho traditions predate modern shoyu and have a continuous production history"}

Source

Japanese Farm Food — Nancy Singleton Hachisu

Cross-Cuisine Parallels

• {'cuisine': 'Southeast Asian', 'technique': 'Nam pla/nuoc cham/prahok fish fermentation', 'connection': 'The global fermented fish sauce family — Japanese gyosho traditions are the East Asian members of this category, sharing the salt-protein enzymatic hydrolysis mechanism while producing distinct regional flavour profiles'}
• {'cuisine': 'Roman/European', 'technique': 'Garum fermented fish sauce', 'connection': 'Ancient Roman garum and the modern European garum revival replicate the same chemistry as Japanese fish sauces — contemporary restaurant fermentation programs often bridge these traditions deliberately'}
• {'cuisine': 'Korean', 'technique': 'Aekjeot (saeujeot liquid, myulchi aekjeot sardine sauce)', 'connection': 'Korean liquid fish sauces used as kimchi seasoning and general condiments — the closest regional parallel to Japanese shottsuru/ishiru in terms of production method and culinary application'}