Question: What is the date of the first game played by the American professional basketball team based in Massachusetts?

Context paragraphs:
List of Boston Celtics head coaches: The Boston Celtics are an American professional basketball team based in Boston, Massachusetts.  They play in the Atlantic Division of the Eastern Conference in the National Basketball Association (NBA).  The team is owned by Wycliffe Grousbeck and coached by Brad Stevens, with Danny Ainge as the general manager.  Founded in 1946, their 17 NBA Championships are the most for any NBA franchise, and their eight consecutive NBA championships from 1959 to 1966 represent the longest consecutive championship winning streak of any North American professional sports team to date.  They play their home games in the TD Garden.

NBA Africa Game 2015: The National Basketball Association (NBA) Africa Game 2015 was an exhibition basketball game played on August 1, 2015 in Ellis Park Arena in Johannesburg, South Africa.  It was the first NBA game, and the first game involving any major North American professional sports league, to take place on the continent of Africa.  It was contested between Team Africa, featuring NBA players and alumni that were born in or had parents born in Africa, and Team World, featuring NBA players from the rest of the world.

Boston Celtics: The Boston Celtics are an American professional basketball team based in Boston, Massachusetts.  The Celtics compete in the National Basketball Association (NBA) as a member of the league's Eastern Conference Atlantic Division.  Founded in 1946 and one of eight NBA teams (out of 23 total teams) to survive the league's first decade, the team is owned by Boston Basketball Partners LLC.  The Celtics play their home games at the TD Garden, which they share with the National Hockey League (NHL)'s Boston Bruins.  The franchise's 17 championships are the most of any NBA team, and account for 24.3 percent of all NBA championships since the league's founding in 1946.  As a percentage of championships won, the Celtics are the most successful franchise to date in the major four traditional North American professional sports leagues.

Saigon Heat: The Saigon Heat (Vietnamese: "Sài Gòn Heat" ) are a Vietnamese professional basketball team based in Ho Chi Minh City, Vietnam.  They play in the ASEAN Basketball League.  Since the 2014 season, the Heat's home games are played at the CIS Arena on the campus of the Canadian International School in District 7.  Saigon Heat is the first professional basketball team based in Vietnam.

Lawton-Fort Sill Cavalry: The Lawton-Fort Sill Cavalry was a professional basketball team based in Lawton, Oklahoma.  They played in the Premier Basketball League after having been in the Continental Basketball Association.  They have one PBL championship and also were the two time champions of the CBA.  The original team was known as the Oklahoma City Cavalry, which competed in the CBA in Oklahoma City from 1990 to 1997 – when they were league champions.  Rochester won the first game of the best of three 2011 championship series 105–101 (in Rochester on April 15, 2011).

2017–18 NBA season: The 2017–18 NBA season will be the 72nd season of the National Basketball Association (NBA).  The regular season will begin on October 17, 2017, earlier than previous seasons to reduce the number of "back-to-back" games teams are scheduled to play, with the 2017 runners-up Cleveland Cavaliers hosting a game against the Boston Celtics at Quicken Loans Arena in Cleveland, Ohio.  Christmas games will be played on December 25.  The 2018 NBA All-Star Game will be played on February 18, 2018, at the Staples Center in Los Angeles, California.  The regular season will end on April 11, 2018 and the playoffs will begin on April 14, 2018.

Saint John Riptide: The Saint John Riptide are a Canadian professional basketball team based in Saint John, New Brunswick.  They compete in the National Basketball League of Canada (NBL Canada) as a member of the Atlantic Division.  The Riptide play their home games at Harbour Station.  The Riptide are one of two professional basketball teams from the province of New Brunswick, the other being the Moncton Miracles.  The team was established in 2007 as the Manchester Millrats, an expansion team based in Manchester, New Hampshire, which played in the American Basketball Association (ABA).  They would later move to the Premier Basketball League (PBL) in 2008, relocated to Saint John in 2010, and renamed in 2016.

Portland Trail Blazers all-time roster: The Portland Trail Blazers, commonly known as the Blazers, are an American professional basketball team based in Portland, Oregon.  They play in the Northwest Division of the Western Conference in the National Basketball Association (NBA).  The Trail Blazers originally played their home games in the Memorial Coliseum, before moving to the Rose Garden in 1995.  The franchise entered the league in 1970, and Portland has been its only home city.  The franchise has enjoyed a strong following; from 1977 through 1995, the team sold out 814 consecutive home games, the longest such streak in American major professional sports.  The Trail Blazers are the only team in the major professional North American sports leagues located in the state of Oregon.  The Trail Blazers are also currently the only NBA team based in the binational Pacific Northwest, after the Vancouver Grizzlies relocated to Memphis and became the Memphis Grizzlies in 2001, and the Seattle SuperSonics relocated to Oklahoma City and became the Oklahoma City Thunder in 2008.

Houston Rockets all-time roster: The Houston Rockets are an American professional basketball team based in Houston, Texas.  The team plays in the Southwest Division of the Western Conference in National Basketball Association (NBA).  The team was established in 1967, and played in San Diego, California for four years before being moved to Houston.  In the Rockets debut season, they won only 15 games.  However, after drafting Elvin Hayes first overall in the 1969 NBA Draft, they made their first appearance in the playoffs in 1969.  After Hayes was traded, Moses Malone was acquired to replace him.  Malone won two MVPs during his time in Houston, and he led the Rockets to the conference finals in his first year with the team.  He also took the Rockets to the NBA Finals in 1981, but they were defeated in six games by the Boston Celtics.  In 1984, the Rockets drafted Hakeem Olajuwon, who led them to the 1986 Finals in his second year, where they lost again to Boston.  In the next seven seasons, they lost in the first round of the playoffs five times.  They won their first NBA championship in 1994, led by Olajuwon, who won Finals MVP.  They repeated as champions the next year, and Olajuwon won Finals MVP once again.  To date, the Rockets have not advanced to the finals again.  The Rockets missed the playoffs from 1999–2003, and did not make the playoffs again until after they drafted Yao Ming in 2002.  Since then, the Rockets have had a winning season in all but two of the next 14 seasons and, led by James Harden, advanced to the conference finals in 2015.

Portland Trail Blazers: The Portland Trail Blazers, commonly known as the Blazers, are an American professional basketball team based in Portland, Oregon.  The Trail Blazers compete in the National Basketball Association (NBA) as a member club of the league's Western Conference Northwest Division.  The team played its home games in the Memorial Coliseum before moving to Moda Center in 1995 (called the Rose Garden until 2013).  The franchise entered the league as an expansion team in 1970, and has enjoyed a strong following: from 1977 through 1995, the team sold out 814 consecutive home games, the longest such streak in American major professional sports at the time, and only since surpassed by the Boston Red Sox.  The Trail Blazers have been the only NBA team based in the bi-national Pacific Northwest, after the Vancouver Grizzlies relocated to Memphis and became the Memphis Grizzlies in 2001, and the Seattle SuperSonics relocated to Oklahoma City and became the Oklahoma City Thunder in 2008.

Supporting paragraphs: 2017–18 NBA season Boston Celtics
Answer: October 17, 2017