The Colle-Zukertort is a deep independent opening in its own right, but is also very flexible. Transpositions to the Queen’s Indian or Slav are often possible. The simplicity of placing the bishop on d3, a knight on e5 and following up with f4 and Rf3 with checkmating prospects is very tempting.

Forgotten Lines and Rare Ideas
 

There are different kinds of classics. There are museum classics, like those dead languages, which are still studied, but which no one any longer speaks.

And there are living classics, which are constantly being renewed: these are 'languages' wich every succeeding generation 'speaks' in its own way, enriching and passing them on to their descendants.

Chess in general and opening theory in particular are no exceptions to the general rule.

Do you play 1.d4, but feel discouraged by the seemingly limitless number of finely honed defensive systems available to Black? If you’re put off by the idea of having to learn massive amounts of theory just to reach a playable middlegame, then The Richter-Veresov Attack: Qd3 Variation might be just what you’re looking for.