Nenryososhomai (tax payment in milled rice) (年料租舂米)
Nenryososhomai was the term for the shomai (milled rice) itself or the system determined by Daijokanpu (official documents issued by Daijokan, Grand Council of State) during the Heian period which required the raw grain collected as So in the provinces to be tithed to the central government as refined white rice
It began when the rice tithed to the central government as Soyocho under the Ritsuryo system (a system of centralized government based on the ritsuryo code) went into arrears in the Heian period, and Denso that was kept as Fudokoku (emergency grain) was tithed to the central government for use in food supplies for government officials. The oldest record is a Daijokanpu in 846.
"Engishiki" (an ancient book for codes and procedures on national rites and prayers) states that 18 provinces surrounding Kinai and the coastal provinces that did not pay Nenryobetsunosokoku paid a total of 24,500 koku.
Originally, it was tithed to the Minbusho (Ministry of Popular Affairs) and then distributed to the various Kanji (government official), but in the tenth century, the Minbusho did not intervene, but each province directly tithed shomai to a given Kanji and this became one of the factors that led to each Kanji becoming responsible for their individual finances.