My latest project is to take the Lichess Open Directory (the full one) as well as the releases of the Chesscom Elite DB and filter them on the same criteria:

-t"tags.txt" -R"roster.txt" --xroster --minmoves 10 --maxmoves 250 --fixresulttags --fixtagstrings --nosetuptags -C -V -N -D -e --plycount -w9999

The “tags.txt” file contains:

WhiteElo >= "2300"
BlackElo >= "2300"
TimeControl >= "180"

and the “roster.txt” file contains:


Here are my finished online strong games:

Also, here is a link to the Python script for extracting a PGN from a ZST archive, starting at 2300 elo. (That can be adjusted, of course.)

I don’t really have room to mirror the Chesscom Elite files, though I do have a complete set, which runs from January 2021 through to May 2024. The whole thing is about 130 GB. I did filter each file, however, and was able to put up a folder called Chesscom Elite Filtered over at MediaFire:

The set comprises the same 2021-01 to 2024-05, but has been filtered with pgn-extract to take out anything below a 2300 rating, or below 10 moves. To remove doubles and non-standard and bullet games, as well as strip comments and variations. Finally incorrect tags have been fixed and openings and plycount have been added. Uncompressed the whole thing is about 11 GB, though here it is compressed, and comprises more like 3 GB.

Games downloaded by chess forum user Splassky, using the Chesscom API.

Paul Morphy, often considered one of the greatest chess players of his time and an unofficial World Chess Champion, did indeed lose games in competitive play, although such losses were rare given his dominant performance throughout his brief chess career.

Morphy’s competitive chess career, predominantly spanning the late 1850s, was marked by numerous victories and a few notable defeats. Here are some instances where Morphy faced losses:

  1. Loss to Johann Löwenthal: Before Morphy was recognized as a top player, he lost games to the Hungarian master Johann Löwenthal in 1850 when Morphy was only 13 years old. They played three games, and Morphy lost two of them.
  2. First American Chess Congress (1857): Morphy participated in and won the First American Chess Congress in New York City, which solidified his reputation as one of the leading chess players. However, during this tournament, he lost a game to Louis Paulsen, a strong player of that era, in their match which Morphy ultimately won.
  3. European Games: During his European tour in 1858-1859, Morphy played against some of the strongest players in Europe, including Adolf Anderssen, whom he defeated decisively in a match. Still, he lost a few individual games throughout his European engagements, showcasing that even the best can be bested under certain conditions.
  4. Casual and Consultation Games: Beyond formal competition, Morphy also played numerous casual and consultation games, some of which he lost. These games, often played without serious competitive stakes, sometimes saw Morphy experimenting with different strategies and opening lines.

Despite these losses, Morphy’s record is overwhelmingly characterized by his victories, and he is famed for his clear, strategic understanding of the game and his ability to decisively outplay opponents. His career, albeit short after retiring from active play in his early twenties, left a lasting legacy on chess strategy and opened the way for the modern understanding of the game.

In chess, Elo, Edo, and ECO refer to different systems or classifications, each serving a unique purpose in the context of the game. Here’s an explanation of each:

1. Elo Rating System

Elo refers to a method for calculating the relative skill levels of players in zero-sum games such as chess. It was developed by Arpad Elo, a Hungarian-American physics professor and chess enthusiast, and is now widely used in chess and other competitive games. The Elo system assigns a numerical rating to each player based on their game results against other players. The key points of the Elo rating system are:

  • Rating Differences: The difference in ratings between two players serves as a predictor of the outcome of a match. Higher differences mean a higher probability that the higher-rated player will win.
  • Win Expectancy: The formula computes the expected score for each player, which is the expected number of wins plus half the number of draws.
  • Updates: After each game, the winner takes points from the loser. The amount of points exchanged depends on the expected outcome versus the actual outcome. If a lower-rated player beats a higher-rated player, the points transferred are significantly more than if the result aligns with expectations.

2. Edo Historical Chess Ratings

Edo is a historical chess rating system, similar in concept to the Elo system, but specifically retrofitted to rate players from historical periods before formal rating systems were established. This system was developed by Rod Edwards on his website “,” and it attempts to rate players from as early as the 16th century based on recorded game outcomes. Here are some specifics:

  • Historical Analysis: By applying modern statistical methods and historical game results, Edo ratings provide a way to compare players across different eras, although with certain inherent uncertainties due to the sparsity and reliability of historical data.
  • Purpose: Edo ratings are primarily used by historians and chess researchers interested in assessing and comparing the relative strengths of players from different historical periods.

3. ECO Codes

ECO, short for the Encyclopedia of Chess Openings, is entirely different from Elo and Edo. ECO is a classification system for categorizing chess openings. The system uses alphanumeric codes (A00–E99) to organize the openings based on their opening moves. Here’s more detail:

  • Structure: The ECO codes are organized into five categories labeled A through E, each dedicated to a group of openings with similar moves and strategies (e.g., A00-A99 for Flank openings, B00-B99 for Semi-Open games other than the French Defense, etc.).
  • Utility: Players and analysts use ECO codes to study openings, prepare for opponents, and discuss various lines and variations within particular types of openings.


  • Elo is a numerical rating system to measure the relative strength of players.
  • Edo is a similar concept but used historically to rate players from the past.
  • ECO is a classification scheme for chess openings, not related to player ratings but to categorizing standard opening moves in the game.

Each system plays a critical role in its respective domain within the chess world, whether it’s ranking current players, assessing historical players, or studying and discussing openings.

An unconventional opening that cedes the center to Black in order to prepare a Queenside fianchetto. Allows for flexibility depending on Black’s response.