Kurodo no to (the name of a post) (蔵人頭)
The Kurodo no to, an official position outside of the Ritsuryo system (these positions were known as Ryoge no kan), was effectively the head of the Kurodo dokoro (chamberlain's office) (the nominal head, also known as the Kurodo betto, was also a minister). Handling Imperial papers and conveying statements to Emperor, "Kurodo no to" played a role that functioned something like a secretary to Emperor. Ordinarily, a person in Shii (the fourth rank) was appointed to "Kurodo no to" but was provided with no official court rank. Two people were appointed to the post of Kurodo no to.
As for the order of seats in the Imperial Court, the Kurodo no to occupied the top seats, higher even than the higher ranking tenjobito (high-ranking courtiers). For this reason, he was also called kanzu (a leader). In addition, use of kinjiki (literally, "forbidden colors," seven colors traditionally reserved for the imperial family and nobility) was permitted for him.
In 810 when Kurododokoro was established, FUJIWARA no Fuyutsugu and KOSE no Notari were appointed to the first "Kurodo no to" posts. Corresponding to Fuyutsugu's success in his carrier, "Kurodo no to" came to be assigned to Sangi (councilor) immediately when the sangi post became available. Therefore, the post of Kurodo no to could be said to be a stepping stone to promotion to the court nobility.
Of the two "Kurodo no to" posts, one was assigned mostly to a person at the "Konoe no chujo" post, a post for military officers, and another to a person at the Benkan post, a post for civil officers. Therefore, the term of "Tonochujo" was used to refer to the former personnel and "Tonoben" for the latter personnel. However, exceptions did occur during the Heian period. For example, when the Kura no kami (head of the Bureau of Palace Storehouses) jointly assumed the post of Kurodo no to, he was known as the toto (head-head). It was towards the end of the Heian period that the practice of assigning a "Tonochujo" and a "Tonoben" to "Kurodo no to" was established.