Thank you very much Kei.Isomura-san. Your comment was very usefull as well.

As a baseball term it means an ace pitcher who bats cleanup, but it is also often used figuratively to mean an able, powerful, and important person.

Hi, kei.isomura-san. I have a question. Is there any particular reason that you "comment" instead of "answer" ? If you don't mind, how about to post your answers as answers, not as comments? // When you "Answer", you can start new paragraph with proper spaces in between. It should be much much easier to read. // Also, viewers can see that there is already an answer when browsing the question list. If you "Add a comment", there is only "0 answers" . Thanks.

This come from baseball. In The Japanese Baseball 4th order of player is very important in gamemaking and also many famus Japanese Base ball hitter in this position Ace is came form card game in card no.1 call in Ace also some game No,1 card is very strong in game also no.1 mean Top or best in many prize so on this two mean set together 4 ban ace have mean in Japan as best baseball player. .