Shidachi (受太刀) means "doing/receiving sword" and is one of the two roles in kata of budō and bujutsu, the other being uchidachi (打太刀).
[1][2][3][4] In modern Kendo this is normally written Shidachi (仕太刀).
Shidachi is led by uchidachi who provides a true attack; this allows shidachi to learn correct body displacement, combative distancing, proper spirit, and the perception of opportunity.
Unfortunately, students often act as though they want to test their skills against those of the higher-ranked uchidachi.
In fact, this leads to neither better technique, nor greater spiritual development, because the correct relationship between uchidachi and shidachi has been obscured.