The High School National Championship Tournament (HSNCT) is a premier national tournament run by NAQT every May, typically over Memorial Day weekend. The tournament is a two-day affair, with preliminary rounds Saturday and playoff rounds Sunday. There are also optional scrimmage rounds on the Friday before.
The HSNCT currently draws the largest field of any national tournament. In 2017 it attracted 304 high school teams from 235 different schools. The most common way to qualify for the HSNCT is to finish in the top 15% at a tournament using NAQT questions during the season, though there are some other ways.
Recent HSNCT tournament sets have contained 26 or 27 packets, each of 24 tossups and 24 bonuses. The first two HSNCTs used NAQT's second-generation format of 28 tossups and 26 bonuses, with the possibility of tossups being read for tossup points only and no bonus potential if the end of the packet was reached. From 2001 to 2010, the packets had 26 tossups and 26 bonuses each.
The 2009 HSNCT was the last to use math calculation tossups; since 2010, these have been removed from the distribution. Most HSNCT packets now contain exactly one computation bonus (and never more than one). Packets also contain non-computational math questions.
The 1999 and 2002 tournaments used swiss-pair prelims followed by a round-robin playoff bracket. The 2000 and 2001 tournaments used pre-scheduled prelims followed by the double-elim playoffs. The current tournament format has remained unchanged in its broad strokes since 2003:
On Saturday, the first day of competition, each team plays ten matches. There are fifteen or sixteen rounds, so each team gets five or six byes. HSNCT uses power-matching; each team is guaranteed to play each of its matches against opponents that have a record within one win of its own record. (In other words, if your current record is 3-5, then your next opponent will be 4-4, 3-5, or 2-6.) Teams need to win at least six of their ten matches to continue play on Sunday.
On Sunday, teams that won six matches on Saturday are eliminated by their first Sunday loss, and teams that won seven or more matches on Saturday are eliminated by their second Sunday loss. With a few exceptions, teams on the verge of elimination play each other, while teams that still have one match to lose also play each other. Play continues until all teams but one are eliminated, and the rest of the final standings in the tournament are based on which teams last the longest on Sunday before being eliminated.
From 2001 to 2013, the HSNCT also recognized a Small School Champion. Schools fitting the criteria played as part of the regular tournament Saturday and Sunday. After they were eliminated from the regular tournament, they played in a separate set of playoff rounds that determined the Small School Champion. Since 2014 NAQT's Small School championship has instead been decided at a separate event.