This distance has proved perfect for creating suspense on the base paths. It all starts at first base, where there are as many close plays as routine plays. A speedy baserunner stands a chance of reaching first on many grounders, especially ones not hit right to the infielders or that require long throws. But even then, a superlative fielding play can often nail the runner, even if by the smallest of margins. The infield, therefore, is capable of rewarding outstanding efforts by both runners and fielders in almost equal measure, making it a geometric wonder.
Furthermore, the distance from home plate to second base created by the “diamond,” which is actually a square, is also ideal for creating great drama on steal attempts. Even with a lead off first base, runners are hard pressed to beat the throw of roughly 127 feet.
Just how baseball settled on the 90-foot distance is unclear. It probably evolved during the 19th century, when the game was not well organized and informally played on fields where various existing objects often served as bases, meaning the field was not really square.
A vestige of those early irregular-shaped days, of course, lives on until the present, but in inconsistent outfield dimensions.