What does solving chess mean

To solve chess you have to be able from the starting position to know what the potential outcome will be. 

You can win, equalize or lose but you have to know it from the start what the respective probability are and you do not have perform any calculation, you don't need to know the rule of chess in fact. You only need to know how to move the piece. 

Note that you could "solve" chess for white and not for black. This would mean that chess can be solve only for one or several fist move. 

The none calculation part means that you know what to play whatever the opponent plays and none of its move can change the outcome. 

See this like this. 

You have a room with a door for each legal move your opponent can do, on each door is written what to play next. Each time the opponent play, you go to the door corresponding to his move, play the move indicated on it, and go trough it.

This lead you to another room with a door for each legal moves your opponent can play, with written on it what move to play. 

You go from room to room until the end of the game. 

Each time you pass a door you know that from this point on: 

- There is % of path that lose 

- There is % of path that draw

- There is % of path that win

First move e4, second e5 you go to the e5 door and see  : 

 Play Nf3, from now on there are 50% of the path were you win, 45% were you draw, 5% were I lose. 

Opponent reply Nf6, you go to the Nf6 door

Play  Bc4, from now on there are 55% of the path were you win, 45% were you draw, 0% were I lose. 

Whatever your opponent play, the information for the reply in stored and you know EXACTLY what the potential outcome are. 

@1
"What does solving chess mean"
++ The game-theoretic value of a game is the outcome when all participants play optimally.
Ultra-weakly solved means that the game-theoretic value of the initial position has been determined.

Weakly solved means that for the initial position a strategy has been determined to achieve the game-theoretic value against any opposition.

Strongly solved is being used for a game for which such a strategy has been determined for all legal positions
https://www.sciencedirect.com/science/article/pii/S0004370201001527 

"you have to know it from the start what the respective probability are"
++ It is not a matter of probability. Chess is a draw.

"you could "solve" chess for white and not for black"
++ No, you have to find a strategy for black to draw against all white opposition. 

"you know what to play whatever the opponent plays and none of its move can change the outcome" ++ No, errors by black can change  the outcome from draw to a white win.

"- There is % of path that lose :" ++ Those are errors.

"- There is % of path that draw:" ++ Those are good moves.

"- There is % of path that win:"
++  No, you cannot win from a drawn position unless your opponent errs.

"First move e4, second e5 you go to the e5 door and see  : Play Nf3, from now on there are 50% of the path were you win, 45% were you draw, 5% were I lose."
++ No, it is rather: black draws unless black errs.

https://en.wikipedia.org/wiki/Solving_chess

Thanks for the link. 

I was just trying to explain the concept of solving chess would mean that you can play without calculation. 

And it turned out that "solving " a game can be done at different level. 

No. Solving chess does not mean what the "potential outcome" is after each move. It means that after each move a computer would know which move is objectively the "best move" compared to other possible moves. Normally the best move is calculated depending on how many moves ahead the computer has to look. The more moves into the future the engine is set to look the longer it takes for it to calculate, usually exponentially longer, the more "accurate" the calculation will be, although it depends on the position. When there are fewer pieces by the end of the game sometimes it may mean the computer can calculate quicker.

I don't see how that would be "solving " the game. It looks more  like :

- With this algorithm and amount of calculating power you will find the best move every time. 

What happen if you find a better algorithm or have an increase in calculating power ? The previously solved "chess" game could end up with different outcome. 

I probably have understood the term solved wrongly. The way I understood it, if playing a "solved" game, it does not matter the amount of calculation you put when playing with someone having solved the game, the outcome will not change.