The Best move on a Chess Board has sometimes takes decades or even Centuries to get discovered  .

The below Game Screenshot is a game between Wilhelm Steinitz & Von Bardeleben played in 1895 London .

It is White to move now and Move number 15th .The Move White gave was Qe2. After 78 years it was discovered that the best move in this position was Qa5! .

So it is impossible to find always the best move on the board  . There can be a lot of Good moves also which can also make you win the Game .

The best move sometimes takes decades or even centuries to be discovered. For an example, take a look at a moment from the famous game “The Battle Of Hastings”.

[Title "Wilhelm Steinitz-Curt von Bardeleben, Hastings London, 8/17/1895"]
[FEN ""]
[startply "28"]

1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. c3 Nf6 5. d4 exd4 6. cxd4 Bb4+ 7. Nc3 d5 8. exd5 Nxd5 9. O-O Be6 10. Bg5 Be7 11. Bxd5 Bxd5 12. Nxd5 Qxd5 13. Bxe7 Nxe7 14. Re1 f6 15. Qe2 Qd7 16. Rac1 c6 17. d5 cxd5 18. Nd4 Kf7 19. Ne6 Rhc8 20. Qg4 g6 21. Ng5+ Ke8 22. Rxe7+ Kf8 23. Rf7+ Kg8 24. Rg7+ Kh8 25. Rxh7+

It is White to move and at the time the best move considered to be Qe2. After 78 years, it was discovered that the best move in this position was actually Qa4!

Thus it is impossible to find always the best move on the board. There can be a lot of good moves that could win the game for you.