In 1956, the Northern League used the Shaughnessy playoffs. In the first round, the 1st- and 2nd-place teams (Eau Claire Braves, Winnipeg Goldeyes) played the 3rd- and 4th-place teams (Duluth-Superior White Sox, Aberdeen Pheasants), respectively. The winners advanced to the championship. The first round was a single-game series, the championship round best-of-three.
Visiting teams listed first, home teams second. Winning teams in bold.
| 9/3 | Aberdeen 6, Winnipeg 4 Duluth-Superior 7, Eau Claire 1 |
Aberdeen wins series over Winnipeg, 1 - 0
Duluth-Superior wins series over Eau Claire, 1 - 0
| 9/4 | Duluth-Superior at Aberdeen, postponed, rain | |
| 9/5 | Duluth-Superior 6, Aberdeen 3 | |
| 9/6 | Aberdeen 0, Duluth-Superior 9 |
Duluth-Superior sweeps series over Aberdeen, 2 - 0