Steinitz was the first undisputed world champion, holding the title from 1886 to 1894. Steinitz lost his title to Lasker in 1894 and also lost a rematch in 1896–97. Steinitz had an all-out attacking style that was common in the 1860s and did not unveil his positional style until 1873. His new style was controversial and some branded it as "cowardly." The debate over his positional theories was so bitter that it became known as the "Ink War" but by the 1890s Steinitz's theories were widely accepted and the next generation of top players acknowledged their correctness.
All of Steinitz's successes up to 1872 were achieved in the attack-at-all-costs “Romantic” style, but in the tournament in Vienna in 1873 he unveiled his new "positional" style of play which was to become the basis of modern chess. Lasker, who was especially appreciative of Steinitz’ theories, wrote that his principles of strategy were “the greatest landmark in the history of chess.”
Steinitz’ new positional theory was based on the fact that the position must have some signs or indicators that tell one what plan must be followed. Steinitz defined positional features and discovered that brilliant attacks are often successful only because of weak defense. For him, well-founded attacks were based on the accumulation of small advantages. He began to realize that a player should not look for a winning combination unless he held the advantage in some form.
Of his own play Steinitz wrote, “No great player blundered oftener than I done. I was champion of the world for twenty-eight years because I was twenty years ahead of my time. I played on certain principles, which neither Zukertort nor anyone else of his time understood. The players of today, such as Lasker, Tarrasch, Pillsbury, Schlechter and others have adopted my principles, and as is only natural, they have improved upon what I began, and that is the whole secret of the matter.”
Bobby Fischer wrote, “He is the so-called father of the modern school of chess; before him, the King was considered a weak piece and players set out to attack the King directly. Steinitz claimed that the King was well able to take care of itself, and ought not to be attacked until one had some other positional advantage. He understood more about the use of squares than Morphy and contributed a great deal more to chess theory.”
The following game is from Steinitz’ early period. His opponent was Augustus Mongredien (1807–1888), a corn merchant, a political economist, writer and a leading amateur British master. Born in London, he was the son of a French officer who fled to England after Bonaparte's coup d'état in 1798. Gradually he withdrew from business and devoted most of his attention to literary pursuits. He was a good musician, an excellent botanist and was elected president of the Chess Club in 1839 ; he had knowledge of seven languages. In 1859 Mongredien played a chess match against Morphy and after drawing the first game, he lost the next seven. In 1862 he played in the first international tournament in London, finishing 11th of 14 with 3 points.