There's a lot of talk about World Champions and how they're "undisputed." The only way I think a Chess World Champion can be undisputed is if they hold the title and maintain the world's #1 rating. Not just one. They need to hold both. By my count, and with Chessmetrics' help, that makes the Undisputed Chess World Champion list the following:

1. William Steinitz, 1886-1890

2. Emanuel Lasker, 1894-1902, 1907-1912, 1914-1919

3. Jose Raul Capablanca, 1921-1923, 1927

4. Alexander Alekhine, 1927-1935, 1937-1938

5. Max Euwe, 1935-1937

6. Mikhail Botvinnik, 1948-1950, 1952-1954, 1958

7. Vassily Smyslov, 1957-1958

8. Mikhail Tal, 1960-1961

9. Tigran Petrosian, 1963-1964

10. Robert Fischer, 1972

11. Anatoly Karpov, 1974-1982

12. Gary Kasparov, 1985-2000

13. Viswanathan Anand, 2007-2008, 2010-2011

14. Magnus Carlsen, 2013-2023

Notes:

1. Boris Spassky doesn't make the list. He was only the #1 rated player for about half the months of 1966, when Petrosian held the title. When Spassky held the World Champion title, Fischer was above him in rating, way above him, making Spassky ineligible for the title of undisputed World Champion. Fischer was the #1 player in the world in terms of rating beginning in early 1964, dipping for a brief time below #1 in 1965 -1966, but then towering over contemporaries as the #1 rated player from 1966 to 1972, not something that I believe is widely known.

2. Vladimir Kramnik also does not make the list, which I personally like. In his life he held the world's #1 rated player for one month only, in January 2008, at 2799, a point short of 2800, and at a time when Anand officially held the title.

3. Currently we do not have an undisputed chess World Champion. Carlsen is the world's #1 rated player but lost the title when he failed to defend it in 2023. I wonder how long it will be before we have the next truly undisputed chess World Champion.

Conclusion: The player to have claim to the title of undisputed chess World Champion the longest is Lasker (21 years), followed by Kasparov (16 years), then Carlsen tied with Alekhine (11 years each) for third place. I find that fitting. Each of the four proved himself dominant over time.

DanQuigleyUSA