well said :)

That's true. Something like the Berlin Defense often plays into theory to a point where it's looking very endgame-ish. I hardly think that still constitutes an opening.

Maybe that's when the hyper accelerated, advanced, delayed dragon variation ends, but the opening is still going on.

That would be subconsciously, and i wasnt offended.  Also i dont drink but thanks for the offer.

He was not conscious of the possibility of offending, therefore, unconscious is the correct term. To use subconscious would mean that his id secretly hates you.

Thanks Crosspinner and Ivandh for your opinions. The error comes from the fact that the English "the" is pronounced "de" in Spanish. Guess my mind mixed up English and Spanish at that moment. . .Best wishes

I wish I was bilingual.   But I enough problems with just English.  

 tabor:  Como estan las cosas en Venezuela?

             Necesitamos mas representantes de nuestra patria en las grandes ligas de ajedrez en Europa y los Estados Unidos.  Yo naci en Puerto La Cruz estado Anzoategui.  Vivi en Caracas por 2 anos y despues mis padres se mudaron a los Estados Unidos. 

Bueno ahora para contestar tu pregunta y la misma vez ayudar a otro Venezolano.

The opening ends and the middle game begins almost always at the move known as the 'break'.  The 'break' is usually a pawn move that is the first move of the middle game plan of attack.  It usually occurs as early as move 10 and as late as move 30. I will explain what a 'break' move is a little later on in this post.  The plan of attack and the 'break' move chosen is dictated by (2) two factors: 1. The opening selected, and 2. How Black chooses to defend.  Almost all openings result in (6) characteristic pawn structures.  A good overview and how to handle them as Black or White, of those 6 pawn characteristic pawn structures, is covered in, "Pawn Power In Chess", by Hans Kmoch.  In his book Mr. Kmoch writes about what he labels as 'levers'.  'Levers' are created when two pawns are diagonally adjacent to each other, and each can excute a capture of the other (depending on whose move it is).  [I wish I knew how to post interactive diagrams on this post.  It would help alot with this explanation.]  A 'break' move is usually a pawn move that creates a 'lever' with one of your opponent's pawn.

I wrote earlier that the 'break' move selected is dictated by two factors.  In every opening there are thematic plan(s) of attack.  By studying opening books you learn about those plans of attack in the opening(s) you have chosen to study.  How your opponent chooses to defend determines what thematic plan of attack you will use and also when and where on your opponents pawn structure you will execute your 'break' move.  

 I hope this helps and hopefully answers your question.

Excuse me readers:

First I will acknowledge Tranpo´s salute in Spanish and then I will go on in English.

*

Las cosas por aquí, pues agarradas de la Esperanza de salir de esta porquería de gobernantes.

Con decirte que te envidio tu estancia allí. Hice la carrera en California (añísimos ha) y luego estuve un año en Denver. Digan lo que digan, un gran país. Eso de pertenecer a un team. . . de momento "stand by". Juego por placer y fascinación por el ajedrez. No me place la competencia, eso que estuve en deporte organizado cuando joven.

Cualquier cosa que pueda servirte, a la orden.

*

Well, I think that is about the right answer. . ., the one given by Transpo who says:

Coincidentaly, I was thinking about buying Mr. Kmock´s book when this post appeared.

Thanks amigo Transpo

"The opening ends and the middle game begins almost always at the move known as the 'break'. The 'break' is usually a pawn move that is the first move of the middle game plan of attack."

And then he explains that "break". Yes. There is a moment in the game, after you place initial pawns, Ns, Bs. . . that you "feel" (or sense) that you have to do something, either with the pawns or with more powerful pieces, than simply accommodate them for the fight..

I read once that once you start considering where to place your rooks the opening is at an end and the middlegame has begun. Though I know there are exceptions to this it seems as reliable a guide as any. I have had students ask me to put a number on when the opening is finished and the middlegame reached and ofcourse this is impossible. The theory on the more popular openings goes well into the middlegame and often even into the ending. In general I believe most openings end  from moves 8-12 and the middlegame is reached.

tabor, No doubt by now you have come to realize, after reading some of these excellent replies, that there is no definite time set by the number of moves, and sometimes positions, as to when the opening ends and the middle games begins.  To me, one of the intriguing things about chess is that the only absolute part of chess are the laws.  All else depends on time, position, tempo, etc.  

Hm.... of course, many openings feature early pawn breaks. For example, after 1.d4 d5, 2.c4 is already a pawn break.

When does de opening end?

When de phat piece sings.

tabor,

Muy bueno saber que mi respuesta era la que estabas buscando.  A la orden 

Un (GM) Gran Maestro Venezolano va jugar en un torneo en Panama o Mejico.  Se llama Eduardo Patricio Iturrizaga Bonelli.  La valoracion (rating) de Eduardo es 2609.

I was told the opening was over when you have castled.