Sansho (Japanese pepper) (サンショウ)
Sansho (Japanese pepper; scientific name: Zanthoxylum piperitum) is one of the deciduous shrubs of Rutaceae, Zanthoxylum. Its other names are Hajikami and the English term, "Japanese pepper." Hajikami is another name for ginger, so it's called 'Narihajikami' to distinguish the two. Young leaves have the name as kinome (leaf bud) for edible use. It is forage for the papilionid worm.
It is dioecious, growing to an average height of 3 meters, but tall ones are 5 meters in height. There are two sharp spines on each branch. In rare cases there are stumps (seedlings) without spines, due to mutation. As for the mizansho (female tree) without spines, Asakura sansho, which is native to Asakura Yoka-cho, Yabu City, Hyogo Prefecture, is famous, but sansho without spines are cultivated throughout the country. It has alternate and compound leaves. The leaf is approximately 10 to 15 centimeters long. Five to nine pairs of folioles are oval-shaped, 1 to 2 centimeters, and have sawtooth edges. The backside is whitish by comparison to the top side. The flower, which blossoms around April to May, is yellowish green and 5 millimeters in diameter. The male flower is for edible use as the hanazansho (flower of the Japanese pepper), and the young or ripened fruit of the female flower is used. Its fruit is approximately 5 millimeters in diameter. It is green at first but ripens in red by around September or October, and the black seeds inside the fruit come out by dehiscence.
It's native to East Asia, including Japan.
Congeneric, heterogeneous species
Inuzansho (Zanthoxylum schinifolium)
While sansho has a fragrance and distichous spines, Inuzansho has no fragrance and alternate spines. The fruit of Inuzansho is called 'seisho,' has essential oil, and is brewed privately for use as a cough medicine.
Kahokuzansho (Zanthoxylum bungeanum)
Szechuan pepper, in English
In the People's Republic of China, the pericarp is used as a spice called Hoajao.
Terihasansho (Zanthoxylum nitidum)
It also has medicinal uses in China. There are spines along the centerline of the leaf.
Throughout the ages, it has been used as a spice and in medicine. There was a case where the fruit of sansho was discovered in earthware excavated from ruins of the Jomon period. In Korea, it was used for kimchi (original form) before chili pepper was brought over.
Usage in Japan
Because the young buds and leaves (leaf buds) are bright green, they're used to lend color to Kaiseki ryori (a simple meal served before a ceremonial tea) and are used as suikuchi (a fragrant garnish) for soup dishes. Immediately before using it, smash the leaf's cells by patting it a few times to bring forth its scent. Also, it is used in marinated leaf bud, 'kinome miso' (miso mixed with leaf bud) and 'kinomedaki' (boiled leaf bud with soy sauce) of tsukudani (food boiled in sweetened soy sauce). It is also used as a flavoring and coloring ingredient in spring dishes such as bamboo-shoot rice and chirashi zushi (vinegared rice with thin strips of egg, pieces of raw fish, vegetables and crab meat arranged on top).
The flower (Hanazansho) is used as suikuchi for a dish or in tsukudani.
The immature fruit (Aozansho, Mizansho) is boiled to make tsukudani.
The dried powder (called kona (powder) sansho) of the ripened fruit pericarp is used as flavoring that cleans away the odor of grilled eel, as a flavoring ingredient in miso soup, and as an ingredient in shichimi togarashi (a ground mixture of red pepper and aromatic spices). Regarding snacks, it is used in the salty-sweet sauce for gohei mochi (gohei rice cake), sansho arare (sansho cubic rice crackers) (sweets), snacks and sansho mochi (sansho rice cake) (also called kirizansho), which is a sweet rice cake.
For tsukudani, there are kinomedaki (kelp, berries and leaves of sansho for its ingredients), sanshokonbu (kelp and berries of sansho for its ingredients), aozansho, mizansho and chirimenzansho (small dried fish and berries of sansho for its ingredients).
The wood is used to make pestles.
The uses of 'Hoajao' in China
There is a distinct, congenic species, Kahokuzansho (Zanthoxylum bungeanum, or Szechuan pepper in English), called Hoajao in China, and only the pericarp of the fruit is used.
It is frequently used in Szechuan food. The pericarp is added to food cooked by boiling or stewing, stir-fried dishes, and Sichuan-style bean curd (tofu and ground pork spicy taste) for flavoring. By adding the dried powder to the dishes last, the tongue gets the uniquely electrifying flavor sensation characteristic of Szechuan food. It is also used as an ingredient for five-spice powder.
It is called Hoajaoen, which is made by mixing equal amounts of roasted salt and Hoajao powder and is eaten with deep-fried food.
The pericarp is also used in medicine. In traditional Chinese medicine, 'hoajao' is also called kusho, and it's considered to have stomachic, pain-relief and anthelmintic actions. It's used in Daiken chuto (used for stomach ache and abdominal fullness) and Ubaigan (used mainly for gastric disorders).
In the Japanese pharmacopoeia, the ripened pericarp of the elementary and congenic species, from which the seeds are removed as much as possible, is regarded as an herbal medicine called sansho. It's an ingredient for the pharmacopeial bitter tincture and medicated liquor of the lucky charm called toso (New Year's spiced sake), which is enjoyed on New Year's Day. The pungent components of the fruit are α-Sanshool and sanshoamide. It also includes fragrant essential oils such as geraniol, along with dipentene and citral.
The Sansho trees is sometimes infected with swallowtail worms. Because the voracious swallowtail worm is very large, it could eat up all leaves alone and strip it naked down to a stump, so attention is required.