The base of chess

How would you define chess ?

For example: opening, developing and attacking ?

What would each one involve ? What's the goal of them ?

When is an opening goor or bad ? What daes developing exactly mean ?

Thank you!

An incremental turn based fight for superior "force" or "influence" around the opponent's king.  Because this cannot happen immediately, but still looking toward this goal, players value space and time/tempo.  Space is useful because ample space vs the opponent's cramped space automatically means superior mobility/maneuverability and tempo because if only 2 out the last 5 moves were useful for you then it's as if you have lost turns.

So I would say chess at it's core is a fight for mobility, but also (and more classically) a fight for time, space, and force.

The opening is from the first move until at least one player has finished their development.  Ideally/often finishing development means the knights and bishops have been given useful squares where they influence the center, the queen has moved 1 or 2 squares away from her starting square, and the king has castled so that now the rooks are connected along an otherwise empty back rank where they're free to go to open (or other important) flies.  And these are the goals of the opening.  To claim some central space with pawns, to develop to useful squares as quickly as possible, and to castle.

By the way to develop quickly means as few pawns moves as possible (pawns are not development) and useful developing moves usually means to squares where they influence the center.  For example a knight on f3 attacks d4 and e5.

Attacking successfully goes back to the idea of chess as a whole... to have superior mobility in an area and often to meet that goal you want more space (pawns further up the board) and force (more pieces) than your opponent.  An attack can be on a king, or just in an area in general (for example attacking the queen side).

A necessary requierment of exerting lots of force in an area is to get pawns out of the way.  Both enemy pawns and friendly pawns.  Sometimes you get your pieces in front of your pawns and sacrifice to remove the enemy pawns.  Perhaps the more common to get around the pawns is simply by exchanging pawns.  Every time pawns are exchanged "lines" are opened (open files, diagonals, or ranks).  And you then attack using these lines.

Putting these ideas together (force/space/get around the pawns) an attack is usually set up by claiming space with your pawns in an area (kingside or queenside), bringing many mobile pieces to that side of the board, and then sacrificing to remove the opponent's pawns and rushing in or pushing pawns to open lines and rushing in.

The goal of an attack is to have superior mobility/force in that area.  For example you may infiltrate into the enemy position and have 3 attackers to their 1 or 2 defenders.  With more pieces and space you can generate more threats than the defenders can handle and when you do you will win material with tactics one way or another.

A good opening sets you up for a good middlegame.  This means you have claimed some central space with a pawn or two, you have efficiently moved your pieces off the backrank to useful squares where they usually influence the center, and your king is safe (usually castled).

A bad opening usually relies on traps and hopes the opponent will play poorly.  When the opponent plays correctly though a middlegame is reached where he has the superior position usually because he has more central control / more development / or a safer king.

Examples of playing a bad opening is winning a pawn or two at the cost of not finishing development.  When you waste moves making threats while your opponent finishes development this is a bad opening for you.  You may have more material for now, but your opponent has set up for a devastating attack (more space, more force, and a safe king, remember what makes attacks work? )