Food · Fermented foods

Hishi (Water Caltrop / Water Chestnut)

ひし (Hishi)

Also known as: Hishi, Water caltrop, Trapa japonica, Trapa natans var. bispinosa, 菱

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At a glance

CategoryFood
Japanese labeling nameひし
Common Japanese notationsひし, 菱, ヒシ, ヒシの実
OriginAquatic plant Trapa japonica (and related Trapa species), with horn-shaped fruits harvested from ponds and slow-flowing wetlands; principal modern domestic production region Kashihara/Saga Prefecture (Saga-hishi is regional specialty), with very small artisanal production elsewhere
Typical functionsBoiled hishi-no-mi snack — traditional autumn delicacy in Kyushu and Western Japan, Saga regional cuisine specialty, Heritage festival food (associated with autumn harvest festivals)
Regulatory status in JapanStandard agricultural product labeling. Saga-hishi regional specialty positioning is established. Volume is small artisanal scale. Hishi is not a designated allergen.

Hishi (ひし / 菱) is the horn-shaped fruit of the water caltrop plant (Trapa japonica), harvested from ponds and wetlands in autumn and traditionally consumed as boiled snack. Saga Prefecture is the most established modern production region for 'Saga-hishi,' with Kyushu and Western Japan having broader cultural familiarity with hishi as autumn food. The OEM positioning is regional specialty: as a Saga area autumn cultural-heritage food, as boiled hishi-no-mi retail (vacuum-pack and fresh autumn-seasonal), and as festival and regional cuisine specialty. Total volume is small — hishi is not an industrial-scale ingredient but holds clearly defined regional and seasonal specialty value.

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Classification

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Common OEM product categories

Finished-product categories where Japanese OEM manufacturers commonly formulate with this ingredient.

  • Boiled hishi retail (Saga area, autumn seasonal)
  • Vacuum-pack pre-cooked hishi
  • Frozen hishi (less common)

Ingredient profile

Hishi is the fruit of Trapa japonica, an aquatic plant that grows in ponds and slow-flowing waters. The fruit is distinctive: a hard black-brown shell with two horn-like protrusions (giving it the alternative English name 'water caltrop' — caltrop being a four-pronged spike), with a starchy white interior similar in texture to chestnut.

Production: Saga Prefecture (notably Kanzaki area) is the established modern production region. Small artisanal production exists elsewhere in Western Japan and Kyushu. Total annual production is small.

Nutritionally, boiled hishi per 100g provides approximately 88 kcal, 2.5g protein, 0.4g fat, 21.4g carbohydrates with 2.5g dietary fiber. The starchy texture and mild sweet flavor are distinctive.

OEM applications

Boiled hishi-no-mi snack — traditional autumn delicacy in Kyushu and Western Japan, eaten boiled in salted water (similar to peanut snack culture).

Saga regional cuisine specialty — featured in Saga regional cooking and autumn festivals.

Heritage retail — vacuum-pack and fresh autumn retail in Saga area and Western Japan tourism.

For OEM: vacuum-pack pre-cooked hishi retail (autumn seasonal), Saga regional gift retail OEM, and heritage cultural cuisine specialty product collaboration.

Regulatory classification in Japan

Standard food labeling. Saga-hishi regional naming is established but not formally GI-registered.

Hishi is not a designated allergen.

Regulatory classification in other markets

EUNiche specialty positioning.
USANiche specialty in Asian cuisine channels.
ChinaChina has its own water caltrop (菱角 / lìngjiǎo) culture.
KoreaNiche specialty positioning.

Market reference formulations

Example finished products will be added after verification of Saga-area or other origin and product format.

All brand names and product names referenced anywhere on this site are the property of their respective owners. Example entries are provided for informational purposes only and do not imply endorsement.

Alternative ingredients

Related ingredients commonly evaluated as substitutes.

Quick answers

What is Hishi (Water Caltrop / Water Chestnut)?
Hishi (ひし / 菱) is the horn-shaped fruit of the water caltrop plant (Trapa japonica), harvested from ponds and wetlands in autumn and traditionally consumed as boiled snack. Saga Prefecture is the most established modern production region for 'Saga-hishi,' with Kyushu and Western Japan having broader cultural familiarity with hishi as autumn food. The OEM positioning is regional specialty: as a Saga area autumn cultural-heritage food, as boiled hishi-no-mi retail (vacuum-pack and fresh autumn-seasonal), and as festival and regional cuisine specialty. Total volume is small — hishi is not an industrial-scale ingredient but holds clearly defined regional and seasonal specialty value.
What is the regulatory status of Hishi (Water Caltrop / Water Chestnut) in Japan?
Standard agricultural product labeling. Saga-hishi regional specialty positioning is established. Volume is small artisanal scale. Hishi is not a designated allergen.
What products typically use Hishi (Water Caltrop / Water Chestnut)?
Boiled hishi retail (Saga area, autumn seasonal) / Vacuum-pack pre-cooked hishi / Frozen hishi (less common)
Where does Hishi (Water Caltrop / Water Chestnut) come from?
Aquatic plant Trapa japonica (and related Trapa species), with horn-shaped fruits harvested from ponds and slow-flowing wetlands; principal modern domestic production region Kashihara/Saga Prefecture (Saga-hishi is regional specialty), with very small artisanal production elsewhere
What is the INCI / JSCI labeling name for Hishi (Water Caltrop / Water Chestnut)?
JSCI: ひし

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References

  1. 文部科学省 (Ministry of Education, Culture, Sports, Science and Technology) Standard Tables of Food Composition — ひし
  2. Saga Prefecture Saga-hishi production reference

Last updated: 2026-04-28. Ingredient entries are reviewed at least annually against current regulatory listings.

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