Opening repertoire study with spaced repetition (+ database and game collections)

The past couple years I've been very interested in spaced repetition (SRS) for learning and memorizing content. I've been using in to memorize kanji, data in various games (e.g. elixir costs in Clash Royale), and anything else where memorization is very useful.

I've been looking to perfect numerous opening lines so I built ChessHQ.com to implement SRS for opening repertoires. I had found another site or two that tries to do this, but I found some of their features frustrating and unintuitive, so I usually just build my own solutions in cases like those.

If you don't know what SRS is, it's a memorization system where you review material in increasingly longer intervals. For example, you might study an opening line, then review it 4 hours later, then 8 hours later, then a day later, etc. If you fail a review (in this case, make an incorrect move), your level drops and you review the material again sooner to reinforce retention.

The repertoire builder lets you build opening trees which are all of the moves/lines you want to study:

You can also browse the ECO book to find openings, view master games that have the same opening, and import the opening automatically into a new or existing repertoire:

Other repertoire features include:

• Writing personal notes for each position
• Searching for and copying public repertoires other users have built
• Access to Stockfish 14 (soon 14.1 or newest Stockfish) in browser
• Add moves to the repertoire via the master game move list below the board

The following features are planned:

• Ability to change the lesson system to breadth-first instead of depth-first
• Automatic saving of arrows/circles drawn on the board for each position
• View stats on a repertoire, such as average move time, accuracy, problem positions, etc.
• Import line into repertoire from any database or collection game, up to any specific move
• Customization of SRS intervals
• Customization of board sounds and themes
• Export a repertoire as PGN including all possible variations

Other features include a database of ~5 million master-level games and the ability to build game collections. Game collections are shareable so you can send them to anyone (even if they don't have an account):

If there is interest, I also plan to implement a coach system which would have the following features:

• Collaborative chess board
  • Students can join a private group study session
  • All participants can text chat
  • All participants see live board changes as they are made
  • Load positions by FEN, PGN, or a game from a collection
  • Grant board control to another participant
  • Coaches and students can replay session (board state and chat) for up to six months (potentially longer; need to work out the infrastructure)
    
    • Can share the replay with a student who was absent from the session
• View students' repertoires and study progress
• Identify positions the student is struggling with
• Add notes to students' repertoire positions
• Assign problem sets and repertoires to students
• Share game collections with students

Please let me know if you encounter any issues. Development is very active and I will be monitoring the error logs to fix any issues as they arise.

wow the website is really great, i am definitely going to use it for studying openings

Hi! 

Just want to jump in to say that your website looks great, but it seems it doesn't work for me.

It keeps loading like this:

Is the website still supported? Hope so  

Does it cost money?

looks very cool, I cant access the website is it still working