Formal titles began only in 1950, and international ratings in 1970. In Szen's era, international tournament competition was very rare, with long-distance travel being both cumbersome and expensive. The website Chessmetrics.com assigns retrospective historical ratings, using modern mathematical algorithms, based on available results.
Formal titles for chess players and international rating systems were introduced in 1950 and 1970, respectively. During Szen's era, international tournaments were infrequent due to the challenges of long-distance travel. The Chessmetrics website uses modern mathematical algorithms to calculate historical ratings based on available game results.