possible chess positions per move

if you've ever wondered how many different positions can occur, here they are just until move 7. you can only imagine how gigantic these numbers will get for a normal chess game that is somewhere between 25-50 moves - (note: a move is a play for white and black combined, a single play for one player is called a ply)

after 1 move:                                           400

        2 moves:                                   197,281

        3 moves:                            119,060,324

        4 moves:                       84,998,978,956

        5 moves:                 69,352,859,712,417

        6 moves:          62,854,969,236,701,747

        7 moves:   61,885,021,521,585,529,237

the average possible legal moves per ply are steadily increasing from ~20 to ~30

Crazy

if you were to calculate the reasonable or best moves, let's say 5 for a ply, it would go something like this - after 1 move: 25 - 2 moves: 625 - 3 moves: 15,625 - 4 moves: 390,625 - 5 moves: 9,765,625 - 6 moves: 244,140,625 - 7 moves: 6,103,515,625

as you can see, even with a pretty small amount of "normal" moves, it shoots off super quickly

luckily, when reasonable play is the main consideration, there are aspects of the middle game that keep the number of positions from increasing exponentially. examples would be dealing with check, protecting against tactics positionally, attacks on a Queen where it needs to be protected in some way on the next move, blockading or pushing past pawns, and any number of aspects of a specific position on the board. the choice of squares for a retreating bishop and how its placement will affect the continuation of the game. there are probably many more things that will limit positional diversity.