In Chapter 3 of A Separate Peace, Finny names his game of blitzball after the German blitzkrieg, battle tactic of an overwhelming attack used in World War II. In this game, Finny alters the rules suddenly and without warning, giving himself the advantage in this game of competition. Because of these unexpected alterations, no one can play blitzball as well as Finny who "brought his own athletic gifts to their highest pitch":
To escape the wolf pack which all the other players became, he created reverses and deceptions and acts of sheer mass hypnotism which were so extraordinary that they surprised even him.
Finny loves competition and he loves to win. So in order to have fresh competition and to win, Finny creates the rules as he plays blitzball just as he breaks the 100 yard free-style record--because he can. He always "wanted to see if I could do it"; Gene states in Chapter 3 that Finny "seem[s] too unusual for--not friendship , but too unusual for rivalry.
Interestingly, in playing blitzball, there are no teams; everyone is the enemy. This is significant when placing the game in relation to Finny, who feels he must defeat everyone. Thus, there is a military aura to Finny's game.