This paper is concerned with the information dynamic analyses on American football games: One is the game in Eastern University American Football League, National Defense Academy vs. Chiba University, and the other is the Rice Bowl (Japan Championship)2020 Final, Fujitsu vs. Kansai University. The former game is so called one-sided one, for National Defense Academy keeps the advantageous position against Chiba University throughout the game except at the normalized time η=0.25. In the range that the normalized time η is greater than the value of 0.75, the model curve of ξ =η7 shows good agreement with game data. It is found that the game point is at the normalized time η 0.9, where the game outcome becomes definitive and is the cross point between the certainty of game outcome ξ and the uncertainty of game outcome ς. The latter game modelled by ξ=η1.5 is typical one-sided one, and the game point is at the normalized time η0.62. The two characteristic points in American football become evident through the present work, viz. (a)rules are rational and well organized, though sometimes they are too complicated, and (b)anyone can easily participate in the game not only as player, but supervisor, coach, cheer girl or member of cheering party, and/or supporter.
