[bradly]

This is really interesting! Thanks for sharing. What are the average number of moves per puzzle in the top groups? Do they all end up being 5+ moves or can there be 2800+ puzzles with only 2 or three moves?

[drw]

There certainly can be short difficult puzzles, but as I mentioned elsewhere, I think the current 4000-rated puzzles look like outliers and may be removed.

  +----------------+---------+-------------------+
  | ratings_band   | count   | avg_move_count    |
  |----------------+---------+-------------------|
  | ...            |         |                   |
  | 3000-3099      | 917     | 3.9400            |
  | 3100-3199      | 434     | 4.1244            |
  | 3200-3299      | 282     | 4.2766            |
  | 3300-3399      | 144     | 4.7500            |
  | 3400-3499      | 206     | 4.9515            |
  | 3500-3599      | 131     | 4.9237            |
  | 3600-3699      | 104     | 5.0481            |
  | 3700-3799      | 86      | 5.3256            |
  | 3800-3899      | 114     | 6.4035            |
  | 3900-3999      | 43      | 5.9302            |
  | 4000+          | 5       | 1.6000            |
  +----------------+---------+-------------------+

[bradly]

Thank you for sharing the information.

By the way... I really enjoy chess.com. The recent addition of getting to retry your game mistakes is really cool. I'd love to see those kept overtime and be able to retry them all in a random order later.

[drw]

Definitely on the roadmap.