Occasionally while playing on line I run into players who cannot tell the difference between tactics and blundering. Take the following position:
|White to move|
My 1600-rated opponent (white), instead of playing the logical 4.Nxe5, thought he was playing “tactical chess” when he played 4.Bf7+ which is not a tactic, it's an outright blunder. He was left with nothing but a N in play and you can't checkmate with just a N.
In the article Purdy stated his aim was not to show how the precise moves chosen by Capablanca could all be worked out by an average player, but simply to show how to think in such positions. Purdy makes the astute observation that if the student can learn to plan logically, he will avoid serious errors and recognize such errors when made by his opponent. He also adds that you should not become discouraged when you play a move that is not quite as good as the master's. The difference between moves often is very small and such nuances only matter at the GM level. The thing is to avoid moves that are really against the spirit of a position. The interesting thing about this game is that we see in Capa's play how the balance of power edges by almost imperceptible degrees in his favor.
A plan will aim at one or more of the following four objectives and according to which side has the initiative. For example, if you have a strong initiative you do not need to bother with trying to remove your own weaknesses but rather to exploit the opponent’s.
The four possible objectives:
1. Exploiting enemy weakness(es)
2. Removing enemy strength(s)
3. Removing your own weakness(es)
4. Establishing your strength(s).
In actual practice, planning is always simpler than this list would make it appear.