How many moves constitutes a chess opening? At what point is the "opening" finished and the middlegame begun?

Generally speaking it is around the first 10 to 15 moves. This is not concrete by any means, but it gives you a rough idea. It is the phase in which both sides are developing their pieces and getting their kings to safety (castling). There are sometimes exchanges in the opening. Most common exchanges in the opening are pawns and sometimes a minor piece. If one side plays a 'Gambit', they may even give up material such as a pawn or minor piece for smooth and swift development, instead of exchanging for equal material. The idea is usually to gain the 'initiative' and begin a quick attack.

The middlegame in chess refers to the portion of the game that happens after the opening. There is no clear line between the opening and middlegame, and between the middlegame and endgame. In modern chess, the moves that make up an opening blend into the middlegame, so there is no sharp divide. At elementary level, both players will usually have completed the development of all or most pieces. The king will usually have been brought to relative safety. However, at master level, the opening analysis may go well into the middlegame.

Likewise, the middlegame blends into the endgame. There are differing opinions and criteria for when the middlegame ends and the endgame starts. Factors such as control of the center are less important in the endgame than the middlegame. In endgames the number of pieces and pawns is much reduced, though even after queens are traded, one may talk about a "middlegame without queens". The key issue is often said to be: when the kings are safe to play an active role, then it is an endgame.

In my opinion, your game would still be considered in the opening phase as several minor pieces have not been developed and neither side has castled yet.

Hope that helps!

Hello;

In general there are two answers to your question:

1. The opening is that part of the game when the pieces are being developed, most of the pieces are still on the board. Typically castling happens in the opening.

2. Most books say that the opening is the first 5 to 10 moves. This is a very general kind of rule of thumb, not an absolute.

In the game you posted ... I would say that the game is still in opening stages -- neither side has castled.

Gens Una Sumas,

Bill

The chess opening finishes when one of both sides has developed most of its pieces and/or castled