Toso is the name for medicinal alcoholic beverages that people drink on New Year's Day in the hope of being free from noxious bad spirits that cause illness and other misfortunes during the coming year, as well as for their longevity. As shown by the old saying, 'A family will be free from illness if a person drinks it, and people residing within four kilometers will be free from illness if all people in a family drink it,' it is indispensable for celebrating the New Year.
Toso (屠蘇) means to slaughter 'so' (蘇), a kind of demon.
It is prepared by soaking tososan (a mixture of several medicinal herbs) in sake with mirin (sweet sake) and sugar added, and people drink it using three types of cups: a small one, a medium-size one and a large one.
Although the order of drinking varies from region to region, officially it should be had in the order of age, from youngest to oldest. The above-mentioned order, which derives from the Chinese practice, originally implied the tasting for poison by young persons. In Japan, however, the practice of drinking with the head of the family first has been common since the Meiji period or the beginning of the Showa.
Toso is usually served with tosoki, a set of sake utensils. Tosoki consists of a decanter into which tososan, sake and mirin are put, the cups into which toso is poured, a stand on which the cups are arranged in layers, and a tray on which the above items are set. There are varieties of tosoki, including lacquer ware, ceramics, glassware etc.
One theory asserts that tososan was prescribed by Hua Tuo, a great doctor in the Three Kingdoms period (China). Although there are varieties of prescriptions, "Compendium of Materia Medica" listed Atractylodes lancia, shaved cinnamon bark, Ledebouriella seseloides, Smilax china, Rhubarb, Chinese aconite and small red bean. In the current day, highly poisonous substances like Chinese aconite aren't used but instead Japanese pepper, Asiasarum root, Ledebouriella seseloides, cinnamon, dried ginger, Atractylodes rhizome and Platycodon root, etc., are generally used. It is said that tososan is useful as a stomachic and is effective against a cold if taken during the first stage.
Specifically, it contains crude drugs that are effective for warming the body, strengthening gastrointestinal function or preventing the onset of a cold, such as root of Atractylodes rhizome (okera), nut of the Japanese pepper (sansho), root of Ledebouriella seseloides (bofu), root of Platycodon (kikyo), bark (nikkei) of cinnamon (keihi), skin (chinpi) of Japanese orange (mikan), root (uzu) of aconite (torikabuto) and rhubarb, etc. The foregoing is provided, however, that aconite (also a toxic substance) and rhubarb (also used as a cathartic), which have strong effects, aren't used.
It is believed that the practice of drinking toso on New Year's Day began in the era of China's Tang dynasty and in the Heian period of Japan. At the Imperial Court, it was customary to drink toso as the first cup, byakusan as the second cup and doshosan as the third cup. Court nobles used either toso or byakusan. Later, the Muromachi bakufu (Japanese feudal government headed by a shogun) used byakusan and the Edo bakufu used toso. This practice eventually spread among ordinary people, and doctors would distribute tososan in return for their medicine fee. Even today, pharmacies inherit the above practice and distribute tososan to their customers as year-end gifts.
The practice of drinking toso is basically endemic to western Japan, namely the Kinki region westward, while in other regions people often refer to the celebratory drink of the New Year (needless to say, it is normal sake that don't contain tososan) as 'otoso.'