Although 'Sanchuro' appears in some historical sources including 'Taikoki', it is unclear whether they really functioned or not; it is considered that they were placed temporarily, or placed as posts to give some authority to the three.
「太閤記」などの史料にはでてくるが、実際に機能したかは不明で、臨時職あるいは、権威付けのための役職とも言われている。