“You should not have a favorite weapon. To become over-familiar with one weapon is as much a fault as not knowing it sufficiently well. You should not copy others, but use weapons which you can handle properly. It is bad for commanders and troopers to have likes and dislikes. These are things you must learn thoroughly.”
This quote from the legendary swordsman, Miyamoto Musashi, is highly applicable to chess in general and in particular the openings. Whilst many people believe it is an advantage to have pet opening variations I beg to disagree.
There are several reasons for this, the first being that whole idea of having to ‘know’ openings by rote is based on a misunderstanding. When someone has a broad understanding of chess and many different types of middle games they naturally know where there pieces belong in the opening. This in turn hugely diminishes the need for remembering exact variations as the right moves can simply be hung on hooks of understanding. Even if you don’t remember which move you should play you’ll be able to work it out. And sometimes it’s possible to find stronger moves than the ones recommended by established theory.
The effect of having favorites may be even more pernicious if the desire to defend them through thick and thin leads to a loss of objectivity. With an emotional investment in particular methods of play there can be a desire to see only rosy outcomes, and this in turn can corrupt someone’s judgement as a whole. I went through this with the Modern Defense (1…g6 against anything) and found myself consistently overestimating Black’s counter play. It was only after broadening my palette with other defenses (such as the Nimzo-Indian and 1.e4 e5) that I started to gain greater objectivity. These days I find it difficult to play the Modern at all , much preferring to have some pieces solidly planted in the centre.
What should someone do if they play a selection of pet lines? As far as their overall development as a player is concerned I’d strongly suggest finding alternatives so as to expand their horizons and develop a broad sweep of ideas. And whilst I know this contradicts what many people say I’d rather side with Musashi.