1920 in Canadian football 1920 in Canadian football CIRFU and IRFU adopted a four-yard Interference rule while the CRU opted for three yards of Interference. ARFU played games with 12 players per side and introduced the snap-back. The reduction in the number of players was done for monetary reasons as train rates were high after World War I. The CRU would make the same changes in 1921. The MRFU champion Winnipeg Victorias were unable to field a full team for the WCRFU finals and withdrew from competition. The MRFU wanted to substitute the second place University of Manitoba Varsity team but the SRFU refused
Comparison of American and Canadian football and half Canadian/U.S. rules. Thus, many of the similarities and differences between the Canadian and American games indeed came out of this original series where each home team set the rules. For instance, Harvard, because of a lack of campus space, did not have a full-sized rugby pitch. Their pitch was only long by wide with undersized end zones (slightly less than the 53⅓-yard width of the current regulation-sized field for American football). Because of the reduced field, the Harvard team opted for 11 players per side, four fewer than the regulation 15 of Rugby Union. To generate more offense,