1951

Japan's 19-year-old Shigeki Tanaka upset his favored countrymen and Greek national champion Athanasios Ragazos to win in 2:27:45. One of the race's youngest winners, Tanaka - a Hiroshima native - provided an exciting and swift run over the Newton hills to finish 2 minutes, 30 seconds ahead of American John Lafferty (2:31:15).

1952

On a scorching 88-degree day, Indian runner Doroteo Flores of Guatemala survived the wretched conditions to win by almost five minutes in 2:31:53. Flores, a laborer in a Guatemala mill, took the lead from countryman Luis Velasquez near the 10-mile mark in Natick. Appearing undaunted by the oppressive heat and humidity, Flores breezed through the remainder of the route to finish ahead of American Victor Dyrgall.

1953

Once again the course record fell - this time to the lightest winner ever to win the Boston Marathon. Japan's Keizo Yamada, who weighed just 108 pounds and stood only 5'2", shed the leaders on Heartbreak Hill and finished 28 seconds ahead of Finland's Veikko Karvonen. Yamada was clocked at 2:18:51. Sweden's Karl Gosta Leandersson, the 1949 winner, provided a record-setting pace for the first 19 miles with Karvonen and Yamada giving chase. The race marked the emergence of John J. Kelley, a Boston University trackster, who secretly wore the B.A.A. unicorn and colors. The "Younger" Kelley finished fifth in 2:28:19.

1954

Runner-up the previous year, Finland's Veikko Karvonen upset a stellar field that included world record-holder Jim Peters of England, Japanese champion Karau Hiroshima, Finnish champion Erkki Puolakka and American AAU champion John J. Kelley (no relation to John A. "The Elder" Kelley). Peters forged a strong pace during the middle third of the race with Karvonen closely following. As Peters' effort was hampered by severe leg cramps in West Newton, Karvonen carried the lead over the final miles to win by just over two minutes in 2:20:39. Olympic champion Delfo Cabrera of Argentina finished sixth.

1955

Hideo Hamamura, a Japanese speedster, staged a great run over the final half of the course, to lower the course record once again. Hamamura came from 10th position to take the lead from American Nick Costes just over three miles from the finish. Hamamura finished in 2:18:22 - 29 seconds better than the old record set by countryman Keizo Yamada in 1953.