The Playing Strength and Style of Mikhail Botvinnik

Reuben Fine, writing in 1976, observed that Botvinnik was at or near the top of the chess world for thirty years—from 1933, when he drew a match against Flohr, to 1963, when he lost the world championship for the final time, to Petrosian—"a feat equaled historically only by Emanuel Lasker and Wilhelm Steinitz". The statistical rating system used in Raymond Keene and Nathan Divinsky's book Warriors of the Mind concludes that Botvinnik was the fourth strongest player of all time: behind Garry Kasparov, Anatoly Karpov and Bobby Fischer but ahead of José Raúl Capablanca, Lasker, Viktor Korchnoi, Boris Spassky, Vasily Smyslov and Tigran Petrosian. The Chessmetrics system is sensitive to the length of the periods being compared but places Botvinnik third in a comparison of players' best individual years (1946 for Botvinnik) and sixth in a comparison of fifteen-year periods (1935–1949 in Botvinnik's case). In 2005, Chessmetrics' creator Jeff Sonas wrote an article which examined various ways of comparing the strength of "world number one" players, some not based on Chessmetrics; and Botvinnik generally emerged as one of the top six (the greatest exceptions were in criteria related to tournament results). FIDE did not adopt the Elo rating system until 1970, by which time Botvinnik's strength had been declining for several years. According to unofficial calculations by Árpád Elo, Botvinnik was the highest-rated player from 1937 to 1954, peaking about 2730 in 1946.

This may seem surprising in the light of Botvinnik's results in the 1950s and early 1960s, when he failed to win a world championship match outright (as reigning champion) and his tournament results were patchy. But after the FIDE world championship cycle  was established in 1948, reigning champions had to play the strongest contender every three years, and successful title defenses became less common than in the pre-World War II years, when the titleholder could select his challenger. Despite this, Botvinnik held the world title for a longer period than any of his successors except Garry Kasparov. Botvinnik also became world champion at the relatively late age of 37, because World War II brought international competition to a virtual halt for six years; and he was 52 years old when he finally lost his title (only Wilhelm Steinitz  and Emanuel Lasker were older when they were defeated). Botvinnik's best years were from 1935 to 1946; during that period he dominated Soviet chess; and the USSR's 15½–4½ win in the 1945 radio match against the USA proved that the USSR's top players were considerably better than the USA's (who had dominated international team competitions in the 1930s).

Botvinnik generally sought tense positions with chances for both sides; hence his results were often better with the Black pieces as he could avoid lines that were likely to produce draws. He had a strong grasp of long-term strategy, and was often willing to accept weaknesses that his opponent could not exploit in exchange for some advantage that he could exploit. He confessed that he was relatively weak in tactical calculation, yet many of his games feature sacrifices – often long-term positional sacrifices whose purpose was not to force an immediate win, but to improve his position and undermine his opponent's. Botvinnik was also capable of all-out sacrificial attacks when he thought the position justified it. Botvinnik saw himself as a "universal player" (all-rounder), in contrast to an all-out attacker like Mikhail Tal or a defender like Tigran Petrosian. Reuben Fine considered Botvinnik's collection of best games one of the three most beautiful up to the mid-1950s (the other two were Alexander Alekhine's and Akiba Rubinstein's).

Kasparov quotes Tigran Petrosian as saying, "There was a very unpleasant feeling of inevitability. Once in a conversation with Keres I mentioned this and even compared Botvinnik with a bulldozer, which sweeps away everything in its path. Keres smiled and said: 'But can you imagine what it was like to play him when he was young?'"