Microsoft Puzzlehunt

The Microsoft Puzzlehunt is a roughly annual puzzle hunt usually held on the Microsoft campus at Redmond, WA, and typically spanning over two days. Currently, teams are composed of up to 12 members, of which at least some number must be Microsoft employees. This number varies from hunt to hunt, and is usually between two and three. Unlike most hunts, the Microsoft Puzzlehunt is written by a collaboration of several different teams, since Puzzlehunt 15. Each round is authored by a different team without any coordination or constraints on the answers or structure. Due to this, finishing the hunt involves solving a final puzzle instead of a typical metameta, and is constructed such that solving puzzles in any round gradually gives more information to solve it.

History
The first Microsoft Puzzlehunt was held in 1999 by team TLA. Thereafter, a tradition where the winner of the previous hunt would host the next hunt. Exceptions were made if that team had hosted too recently, and instead another high-placing team would host instead. In 2009, the writing teams for Puzzlehunt 12 and Puzzlehunt 13 merged to form Puzzlehunt 123. Starting in Puzzlehunt 15, the responsibility of writing hunt was broken down into smaller pieces, and several teams were tasked with separate modules of the hunt. This modular puzzlehunt form would be the new standard format for Microsoft Puzzlehunt, although a single team wrote Puzzlehunt 18.

Puzzlehunt 21, originally scheduled to run in 2020, was delayed to 2021 and hosted virtually off the Microsoft campus, as a result of the COVID-19 pandemic.