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drw

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Chess.com Director of Research roland@chess.com

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More flexible would be a double-quote-region widget which can be applied arbitrarily to any region of a command line:

    emulate -L zsh

    if [[ "$REGION_ACTIVE" -eq 0 ]]; then
        return
    fi

    if [[ "$MARK" -le "$CURSOR" ]]; then
        left_region_bound="$MARK"
        right_region_bound="$CURSOR"
    else
        left_region_bound="$CURSOR"
        right_region_bound="$MARK"
    fi
    length_region="$((right_region_bound - left_region_bound))"

    before_region="${BUFFER:0:$left_region_bound}"
    region="${BUFFER:$left_region_bound:$length_region}"
    after_region="${BUFFER:$right_region_bound}"

    quoted_region="${(qqq)region}"
    cursor_offset="$(($#quoted_region - $#region))"

    BUFFER="$before_region$quoted_region$after_region"
    CURSOR="$((CURSOR + cursor_offset))"
    REGION_ACTIVE=0
bind with eg
    zle -N double-quote-region
    bindkey '\e"'  double-quote-region

The team had to selectively throttle access to that one game and change things around to get through the overload.

I'm trying to pun "paged" with "Phish" and it doesn't work.

But ops was definitely on deck, on the holiday.

Among chess.com players who have played 10+ blitz games and 10+ puzzles, the average difference between their blitz rating and puzzle rating is 45 (blitz rating higher). The standard deviation of the difference is 374.

Among players who have played 100+ games/100+ puzzles, the difference is -205: puzzle rating substantially higher, standard deviation 320.

I'm not sure that it's ideal for ratings to be identical across the domains, but they should correlate to some degree.

Yes, the rating differs by theme quite a bit.

  +-------------------+------------+
  | theme/tag         | mdn_rating |
  |-------------------+------------|
  | Opposition        | 1725       |
  | Passed Pawns      | 1494       |
  | Rooks on Seventh  | 1408       |
  | Pawn Endgame      | 1353       |
  | ...               | ...        |
  | Smothered Mate    | 549        |
  | Stalemate         | 533        |
  | Mate in 2         | 436        |
  | Mate in 1         | 399        |
  +-------------------+------------+
I also like the idea of showing the user's +/- for each theme. Though the data for some themes is better than data for others.

Last month we added 2800, the vast majority automatically derived, though we also prize expert review.

We are thinking of doubling that rate next month.

I'm not sure much can be done about the predominance of certain puzzle types in the very early Rush puzzles. Would you prefer more hung pieces?

But in the later levels, mixing it up by themes/tags is an interesting idea, about which I will make some measurements.

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            |
  +----------------+---------+-------------------+

I am not sure that the 5 specific puzzles maxed out at the 4000 also represent the very best, most fun, and most insightful. Sometimes the reason a puzzle comes up as an extreme outlier is somewhat obtuse, and we are more inclined to remove the puzzle after we see how users interact with it.

For example https://www.chess.com/puzzles/problem/568140 is mostly rated 4000 because ...Qe1+ is so compelling that it pulls in even excellent players, while there's an easy material pickup on the board.

But there are exceptional puzzles throughout the 3000s, like 3500-rated https://www.chess.com/puzzles/problem/769056 , which absolutely anyone can follow, but few can solve on the first try.

The iOS team doesn't see any recent crashes that associate to viewing videos.

If you want to follow up, feel free to email me your chess.com username and the approximate date when you had trouble; the team could look up crashes which happened to that username.

Both my personal and chess.com email addresses are in my profile.

Something we work very hard on at chess.com is the rating of the individual tactics puzzles.

Some of you might enjoy looking at the distribution of our puzzle ratings. Truly hard problems are precious, and we would always like to have more at the high end. The distribution is multimodal because puzzles of different lengths have different modes.

  +----------------+---------+
  | ratings_band   | count   |
  |----------------+---------|
  |   100-199      | 5320    |
  |   200-299      | 2542    |
  |   300-399      | 31542   |
  |   400-499      | 10282   |
  |   500-599      | 4539    |
  |   600-699      | 7644    |
  |   700-799      | 6017    |
  |   800-899      | 5288    |
  |   900-999      | 5109    |
  | 1000-1099      | 5187    |
  | 1100-1199      | 4905    |
  | 1200-1299      | 4369    |
  | 1300-1399      | 8164    |
  | 1400-1499      | 8969    |
  | 1500-1599      | 8430    |
  | 1600-1699      | 8007    |
  | 1700-1799      | 7795    |
  | 1800-1899      | 8143    |
  | 1900-1999      | 9116    |
  | 2000-2099      | 10551   |
  | 2100-2199      | 10261   |
  | 2200-2299      | 7057    |
  | 2300-2399      | 2446    |
  | 2400-2499      | 1225    |
  | 2500-2599      | 1067    |
  | 2600-2699      | 1055    |
  | 2700-2799      | 964     |
  | 2800-2899      | 888     |
  | 2900-2999      | 881     |
  | 3000-3099      | 917     |
  | 3100-3199      | 434     |
  | 3200-3299      | 282     |
  | 3300-3399      | 144     |
  | 3400-3499      | 206     |
  | 3500-3599      | 131     |
  | 3600-3699      | 104     |
  | 3700-3799      | 86      |
  | 3800-3899      | 114     |
  | 3900-3999      | 42      |
  | 4000+          | 5       |
  +----------------+---------+