I don’t know Japanese and havent studied this so hopefully someone can correct me as well. But I dont think it would be right to translate this to the modern meaning of a ship pilot. It more loosely translated to “navigator”.

There are some seemingly good details here[0].

> In Early Modern Japanese there was a word 按針 anjin, literally “searching needle,” which referred to the process of using a compass. At the time, this was the main way in which ships were navigated and so, by extension, the word was applied not just to ship navigation, but also to ship navigators

It goes into more detail about things as well but that is the part that stuck out to me the most.

0: http://japanthis.com/2013/06/20/what-does-anjincho-mean/