Williams and Amherst first met in softball in 1984.
The Ephs lead the all-time series 50-19 through 2018.
| Year | Winner | Location (W/A) |
Score | Tournament |
| 2018 | Williams | W | 3-1 | |
| 2018 | Williams | W | 11-0 | |
| 2018 | Amherst | A | 7-4 | |
| 2018 | Amherst | A | 7-1 | |
| 2018 | Williams | W | 5-4 | |
| 2017 | Williams | N | 9-1 | |
| 2017 | Williams | N | 8-2 | |
| 2017 | Williams | A | 4-3 | |
| 2017 | Williams | W | 5-2 | |
| 2017 | Williams | W | 2-1 | |
| 2016 | Williams | W | 6-3 | |
| 2016 | Williams | A | 7-3 | |
| 2016 | Amherst | A | 7-6 | |
| 2015 | Amherst | A | 6-0 | |
| 2015 | Amherst | W | 9-8 | |
| 2015 | Williams | W | 2-0 | |
|
2014 |
Williams | A | 3-2 | |
|
2014 |
Williams | A | 5-1 | |
| 2014 | Amherst | W | 13-2 | |
| 2013 | Williams | A | 4-2 | |
| 2013 | Williams | W | 8-7 | |
| 2013 | Williams | W | 4-3 | |
| 2012 | Amherst | A | 7-6 | |
| 2012 | Amherst | A | 6-1 | |
| 2012 | Amherst | W | 5-2 | |
| 2011 | Williams | A | 10-0 | |
| 2011 | Williams | A | 8-4 | |
| 2011 | Amherst | A | 5-4 | |
| 2010 | Williams | A | 6-3 | |
| 2010 | Williams | A | 6-4 | |
| 2010 | Amherst | W | 4-3 | |
| 2009 | Williams | W | 8-4 | |
| 2009 | Williams | W | 5-3 | |
| 2009 | Amherst | A | 3-1 | |
| 2008 | Williams | A | 10-6 | |
| 2008 | Amherst | A | 4-2 | |
| 2008 | Amherst | W | 3-1 | |
| 2007 | Williams | W | 4-0 | |
| 2007 | Williams | W | 8-0 | |
| 2007 | Williams | A | 6-2 | |
| 2006 | Williams | A | 9-3 | |
| 2006 | Williams | A | 1-0 | |
| 2005 | Williams | W | 5-4 | |
| 2005 | Williams | W | 9-6 | |
| 2004 | Williams | A | 1-0 | |
| 2004 | Williams | A | 7-2 | |
| 2003 | Williams | W | 3-2 | |
| 2003 | Williams | W | 3-0 | |
| 2002 | Williams | A | 3-0 | |
| 2002 | Williams | A | 4-2 | |
| 2001 | Williams | W | 2-1 | |
| 2001 | Williams | W | 3-1 | |
| 2000 | Amherst | A | 3-2 | |
| 2000 | Williams | A | 5-3 | |
| 1999 | Amherst | W | 3-0 | |
| 1999 | Williams | W | 12-5 | |
| 1998 | Amherst | A | 7-6 | |
| 1998 | Amherst | A | 2-0 | |
| 1996 | Williams | A | 8-2 | |
| 1995 | Williams | W | 3-2 | |
| 1995 | Williams | W | 2-0 | |
| 1992 | Amherst | W | 8-6 | |
| 1991 | Williams | A | 4-2 | |
| 1989 | Williams | A | 15-2 | |
| 1988 | Williams | W | 18-5 | |
| 1987 | Williams | W | 3-0 | |
| 1986 | Williams | W | 11-6 | |
| 1985 | Williams | W | 11-5 | |
| 1984 | Williams | W | 12-2 |