Understanding tempi

I’m trying to understand tempi.  I think strictly speaking, in a chess game both sides are allocated the same amount of tempi (moves.)  It’s just that one side or the other might waste some of it.  Just as in life, everyone gets the same amount of time,  24 hrs per day.  In chess, one move per turn.  When we say we “lose time” toward some purpose, we just mean we waste it, or we fail to spend it toward the intended purpose.

If the purpose is development of pieces in the opening, a move that fails to develop another piece, loses a tempo. 

I might be missing something, though.

In Nimzowitsch’s “My System,” 21st Century Edition, Soft Cover,  “6 The center and it’s demobilizing force,” page 7(board exercise inserted below), at the end of the main line, Nimzowitsch counts white to have 6 tempi to black’s 1.5.  I understand the 1.5 (loss of 0.5 is explained in the annotation to move 7 here) but I don’t understand white’s 6.  I make it 5.  5 white pieces are developed.  Can anybody here account for 6?

Move by move in the main line, I count the tempi for white and black respectively as:

Move.  White tempi, Black tempi

1.    1,1
2.    1,1  loss of material for white at this point, but equal tempi.
3.    2,2
4.    2,2
5.    3,2  and equal material now
6.    4,2
7.    5,2  though black hasn’t moved yet.  Also, minus 0.5 for black for reasons given in the annotation, so actually 5, 1.5.

Do you agree?

Similarly, at the end of one of the variations in this exercise, noted in the annotation here, Nimzowitsch makes white to be ahead by 4 tempi, where I make it 3.  3 developed pieces for white, none for black.

Am I missing something? 

It can be subjective, but a player moves 'with tempo' when his move causes the other player to have to respond in a manner that doesn't help their cause.

If you make a move that could gain tempo, such as by attacking an unprotected piece, and the opponent moves that piece to a better square, you haven't gained a tempo.

The effect of moving with tempo is to get a free move.  In the diagram above, black might eventually want his K in the corner so white hasn't gained a full free move - but he has gained a portion of a move at a time of his choosing...

Thanks, stormcrow.

"In the diagram above, black might eventually want his K in the corner so white hasn't gained a full free move - but he has gained a portion of a move at a time of his choosing..."

By checking the K, white gains a full free move.  With the K in the corner, how does white gain a portion of a move, if I may ask? 

Perhaps black would have eventually wanted to move the K to the corner anyway.  Now, in this particular case, which is totally fabricated, who knows.  But in general, it is possible.  And if this was the case, black would have "saved" a little bit of a move.  But clearly, white has outmaneuvered black in the diagram.

The extreme counter-example is when you tempo your opponent's Q, for example, and he moves it to the square he wanted to be on anyway.  In this case, the opponent loses -0- time.  Beginners do this all the time - the wrong way - when they chase their opponent's unprotected pieces who defend them by pushing center pawns or developing pieces.  Or they play a series of useless checks that drives the enemy K into a great defensive location.

Regarding tempo, many a sacrifice is touched off by a player's refusal to be tempoed.

Also, see "zwischenzug."  This is a one-move intermediate move that finds a tempo in the middle of a common series of moves such as recaptures. 

Got it, thanks. Good explanation.   

Ah yes, I recognize the term intermezzo.  I've experienced the idea in games I think, but didn't put it with the word.  My opponent might be about to capture material.  I might defend, or I might start a threat (intermezzo) elsewhere, putting the question back to my opponent, "do you want to follow through immediately with your capture or do you want to defend against _my_ threat?"  

Old Chess Maxim: "never force the opponent to make a move he[1] want to."

[1] maxim dates back to days when "he" was generic for the gender-indeterminate 3rd person singular pronoun.