Training quote of the day #22: Tigran Petrosian

From the Chess.com article "Chess Plans, Losing Streaks and Petrosian Speaks" by IM Jeremy Silman:

Viktor Khenkin’s question:

There is a widely-held opinion that the only players that enjoy competitive longevity are those who base their play not on the calculation of concrete variations but on positional understanding. In short, their play is founded on general positional considerations. Such a method allows a player to expend less energy, and hence to withstand better the tension of a tournament game. Is this true?

GM Tigran Petrosian:

I do not share this point of view. Positional understanding is indeed a sign of the great practical strength of a player. But with the years this skill also becomes blunted. It must be constantly stimulated and modernized; in other words a player must work on chess art and analyze.

But on positional understanding alone you will not go far. Without sharp tactical vision there is no chance of success. But as a player grows older his calculating capacity is markedly reduced, and he has somehow to compensate for this deficiency. Why did Botvinnik retain for so long his great fighting ability? Because he was able to recognize this irreversible process earlier than others and to ‘reprogram’ himself. In what way? In the same way as I am doing now.

Although I have never been assigned to the category of ‘chess calculators,' in my youth I used to work out at the board an enormous amount of variations. I used to calculate them quite quickly and quite deeply. Today too I can calculate deeply and well, only not for five hours at a stretch. I can now switch on my ‘calculating apparatus’ at full power only once or twice during the course of a game. Therefore I try to choose my openings and build up my play so that there is no need to analyze variations move after move. But if at a critical moment such a necessity suddenly arises, I can cope with this no worse than I used to.