135 Studies And Problems – A whole career of composed problems from J.T. Sanderse.
Archives des problémistes – In French. Problem site from Quebec.
Beautiful Chess Problems – Only a few at the moment, but more promised.
Bruno’s Chess Problem of the Day – Just like it sounds.
BYCA Chess Puzzles – In addition to the collection of puzzles, features a “puzzles league” where you can participate in a friendly solving competition.
Chess Composition Microweb – Featuring various sections on composed chess problems & problem-solving.
Chess Online Problems – Problems galore. More added frequently.
Chess Problems Online – A decent collection, intelligently displayed, from “Mate in One” to “Mate in Six”.
Chess Problems From Around The World – Problems from everywhere.
Chess Problems Of 1001 Years Ago – From the Chess Variants Homepage — really old problems mainly of historical interest.
Chess Problems Unlimited – Not quite unlimited, there are but several.
Chesspro’s Chess World – Problems and instructive games.
Chess Puzzles by GMs – Taken from the games of the greats.
Chess Puzzles Collection – A nice collection taken from real games. Includes an index of the puzzles by theme.
CHEST – Source code (in ANSI C) for a problem solving program.
Classic Chess Problems – 2 and 3 movers from renowed composers.
Endgame Of The Day – An endgame study a day. Also available as a mailing list.
Exeter Chess Club: Studies and Problems – Intro to the world of problems.
GorFo Problem Chess Pages – Has a problem of the month composed by the author, plus an archive of past problems.
Key Moves – A new chess combination (from recent games) every week for your instruction and amusement.
Loiodice’s Chess Problems – Lots of training positions to download.
Manolis Stratakis’ Chess Problems Page – Pretty good page with plenty of problems and puzzles.
MateMaster – Shareware software for solving chess problems.
Mater – Will find any mate that’s there, eventually.
Mat Plus – The best chess problems from magazine Mat Plus.
Practical Chess Endgame – Solve the endgame of the week.
Problemiste – Chess Problem software.
Public Domain Chess Composition Books – 19th Century (mostly) chess problem books in PDF format so you can print them out yourself. Nice!
Retractor – Software for creating Retrograde Analysis chess problems.
The Retrograde Analysis Corner – Retro problems and resources for retro enthusiasts.
Sack The King! – A chess problem a day, with special animated interface to display the solution.
Solving Chess – Tracking the world of competitive chess problem solving.
Torsten Linß’ Problem Chess Pages – Problems and articles from noted composer. Some of the text in German.
Vincent’s Chess Problems Page – Dozens of problems to pour over.