Honnaoshi is a kind of alcoholic drink. It is also called naoshi. It's a product made by blending mirin (sweet rice wine), which is very sweet and is usually employed as a seasoning, with shochu so that the product becomes less sweet and is therefore easy to drink.
In the complimentary sense, honnaoshi is sometimes called yanagikake.
Its name 'naoshi' (literally, improve) is derived from 'improve the taste of a difficult-to drink alcoholic beverage.'
Although it was drunk by many people in the Edo period as a subtype of shochu, today it has minor status. The fact that it was drunk in the summer season after being cooled in a well and was treated as luxury product is seen from the story of 'Aona,' a program of kamigata-rakugo (traditional Japanese storytelling performed in the region of Kyoto and Osaka). It was also used as the principal material of toso (a spiced sake that is used in celebration of the New Year).
Legally, it's called 'drinking mirin.'
According to the Liquor Tax Act, it was once distinguished from 'hon-mirin' (pure mirin), and its tax rate was lower than that of hon-mirin. However, they were later unified.
In the wake of a WTO recommendation issued in the 1990s, the tax rate for whisky was lowered while the rate for shochu was raised. However, honnaoshi was overlooked since it was identified with cooking liquor, and its tax rate was left relatively low. Under such circumstances, some manufacturers of shochu/mirin aimed at honnaoshi as 'tax-saving shochu,' as in the case of low-malt beer. As a result, its sales as an alcoholic beverage increased rapidly toward the end of the 1990s.
However, the Finance Ministry (current Ministry of Finance) didn't overlook the situation, and in 2000 it amended the Liquor Tax Act. Because of that amendment, the tax rate of drinking mirin containing a large amount of shochu (the products whose alcohol content is 23 proof or above, or the products whose content of extracted component is below 8%) was raised to the same level at that of shochu, and consequently there was a sharp drop in the demand for naoshi. Currently, honnaoshi is produced and sold by a limited number of manufacturers.