The First World Chess Championship, 1886
Before 1886, "World Champion" was an informal label, whoever was widely regarded as the strongest player, with no match, title, or governing rule behind it. Wilhelm Steinitz and Johannes Zukertort changed that by contesting a formal match, first to 10 wins, for the explicit title of World Chess Champion. Steinitz won it 10-5, with 5 draws, clinching his tenth victory in Game 20 to establish the championship as an actual institution rather than a reputation.
A match that toured three cities
Played from January 11 to March 29, 1886, the match opened with five games in New York, moved to four games in St. Louis, and finished with eleven games in New Orleans, an itinerary that looks bizarre by modern championship standards but reflected how genuinely new the concept of a formal World Championship still was; there was no fixed template yet for how or where such a match should be run.
Zukertort's fast start, and Steinitz's method
Zukertort actually won four of the first five games in New York, and for a moment looked like the clear favourite. Steinitz's response defined the rest of the match: rather than matching Zukertort's combinative, attacking style move for move, he shifted the games toward the kind of solid, positionally sound structures that played to his own growing theory of strategic chess, the same approach that would soon reshape the entire sport and earn him lasting recognition as the father of modern positional chess.
The turn, and the finish
Once the match reached New Orleans, Steinitz's methodical approach took over completely, he won Game 20 to reach ten victories first, closing out the match before all twenty scheduled games had even been required to run their course. Zukertort's brilliant early form simply could not be sustained across two and a half months of grinding positional resistance.
Why this match, specifically, is the starting point
Chess had unofficial "champions" going back to figures like Philidor and Morphy, but none of them held the title through a codified match with agreed stakes and an explicit championship claim attached. 1886 is where that changes, everything that follows in this list, Lasker, Capablanca, Alekhine, Botvinnik, Fischer, Kasparov, exists within the institution Steinitz and Zukertort created here.
Try it yourself
Play through a Queen's Gambit Declined structure like the one above and ask, at every move, "what is the smallest, safest improvement available," rather than reaching for the sharpest option on the board. That restraint, choosing method over spectacle, is exactly what let Steinitz overturn a four-games-to-one deficit and invent the World Championship in the process.