Is Sumo a form of Martial arts?

Answer 1

{| |- | It is a very ancient art. Wrestling in general has been a competitive event for many thousands of years and could certainly be considered one of the earliest branch of the Martial Arts. Japanese document such matches in the 1500's |}

Answer 2

Yes, while formed for more entertainment purposes, Sumo is an ancient form of martial arts / wrestling. There is more to Sumo than just being "big". It is believed that many sumo were samurai or former samurai, or a "ronin" , which is a samurai which had no lord or master at the time and was looking income. Since that was the case, they were all highly trained fighters.