Question: When did the hockey field where the 2015 Hockey City Classic was played open?

Context paragraphs:
Soldier Field: Soldier Field is an American football stadium located in the Near South Side of Chicago, Illinois.  It opened in 1924 and is the home field of the Chicago Bears of the National Football League (NFL), who moved there in 1971.

Pruitt Field: Pruitt Field is a field hockey field located in Athens, Ohio on the campus of Ohio University.  It serves as the home of the Ohio Bobcats women's field hockey program and opened in 2000.  Pruitt Field is surrounded by Goldsberry Track and acts as the infield for track events.

1996 NCAA Division I Field Hockey Championship: The 1996 NCAA Division I Field Hockey Championship was the 16th women's collegiate field hockey tournament organized by the National Collegiate Athletic Association, to determine the top college field hockey team in the United States.  The North Carolina Tar Heels won their third championship, defeating the Princeton Tigers in the final The championship rounds were held at the Boston College Field Hockey Field in Chestnut Hill, Massachusetts on the campus of Boston College.

2015 NCAA Division I Field Hockey Championship: The 2015 NCAA Division I Field Hockey Championship was the 35th women's collegiate field hockey tournament organized by the NCAA, to determine the top Division I college field hockey team in the United States.  The semifinals and championship match were played at the Ocker Field Hockey Field in Ann Arbor, Michigan from November 20 to 22, 2015.  This was the first time Michigan hosted the tournament finals.

BAF Saheen College Hockey Field: BAF Shaheen College hockey field is a hockey field in Dhaka, Bangladesh.  It is the ground of BAF Shaheen College Hockey Team.  It is the only school hockey ground of Bangladesh containing artificial turf.  A number of national level tournaments are held there every year.  It was constructed in 2014 with a view to provide better infrastructural facilities to its hockey team and to give opportunity at school level to arrange tournaments of international standard.  The construction began in December, 2014.  It was opened in the end of that month making it the first ever artificial hockey turf of school of Bangladesh.

2015 Hockey City Classic: The 2015 Hockey City Classic is a doubleheader of ice hockey games which will be played on February 7, 2015 at Soldier Field in Chicago, Illinois.  This is the 3rd edition of the Hockey City Classic.  The 2015 Hockey City Classic will feature two games, the first of which will be played between Miami (OH) and Western Michigan and the second of which will be played between in-state rivals, Michigan and Michigan State.

Adrian D'Souza: Adrian Albert D'souza (born 24 March 1984 in Mumbai, Maharashtra) is a field hockey goalkeeper from India, who made is international debut for the Men's National Team in January 2004 during the Sultan Azlan Shah Hockey Tournament in Kuala Lumpur, Malaysia.  Adrian has more than 100 International Caps for his country in all competitions.  He has played in all major field hockey tournaments, including the 2006 Hockey World Cup, 2006 Asian Games, 2007 Asia Cup and 2 Champions Trophies.  Regarded as one of the most innovative and daring goal-keepers of recent times, Adrian bought the rushing technique to the hockey field.

Komazawa Hockey Field: The Komazawa Hockey Field was a venue constructed in Tokyo, Japan for the field hockey competitions of 1964 Summer Olympics.  Although there were three hockey fields, it marked the first time the field hockey was played in one single venue for the Summer Olympics since the 1920 Games.

Hockey 9s: Hockey 9s or Hockey Nines is a variation of the sport of field hockey played at international level.  While played on a standard size hockey field, there are a number of variations in its rules, most significantly the reduction of number of players on a team from eleven to nine.

Sakae Morimoto: Sakae Morimoto (Japanese: 森本 さかえ ; born January 20, 1977 in Tenri, Nara) is a female field hockey field player from Japan.  Affiliated with the Tenri University she played for the Japan women's national field hockey team, at two Summer Olympics: 2004 and 2008.

Supporting paragraphs: 2015 Hockey City Classic Soldier Field
Answer: 1924