This post discusses opening preparation in CC. What are key activities to do with ongoing games that run months? What should be the focus of preparation for correspondence chess?

Preparation in OTB chess takes place usually before every tournament or game, providing an opportunity to prepare openings and other improvements or to tailor them to your opponents.

In CC this is not the only need. After finishing a tournament you can set yourself targets for improving and study, but with CC games running months the windows to do this are slim to none.

Given in CC  play you have access to databases, engines and tablebases, books and many other resources, preparation in CC requires also a different focus on specific knowledge and skills.

This suggests there are certain opening preparation activities that are more relevant to CC.  Two key interconnected ones are strategic understanding and repertoire reinforcing. 

The first requires to focus on strategic ideas to enhance your understanding of chess patterns to avoid engine creep. This means developing your chess insight to have you leading, not the engine.

Related to this is preparing openings to a great depth, to control moves progression and branching. You need to have a deep analytic horizon to manage the post development of your pieces.

These activities need to take place both before and during play. Research during games should be targeted to support these strategic insight gaps and to build your repertoire on the go.

Ultimately CC opening preparation is comparable to building a plane while flying. You will need to act on your accumulated knowledge at every stage while you keep deepening your understanding.