Short answers, pulled from the story.
Tafl games are a family of ancient Northern European strategy board games played on a checkered or latticed board with two armies of uneven numbers. They were played in Norway, Sweden, Denmark, Iceland, Britain, Ireland, and Sápmi, and followed Viking expansion as far as Garðaríki in what is now part of Russia.
Tafl games were supplanted by chess in the 12th century across most of Northern Europe. The Sámi variant tablut survived until at least the 18th century and possibly into the late 19th century.
Carl Linnaeus recorded the rules of tablut during his 1732 expedition to Lapland, writing them in his journal Lachesis Lapponica. The rules were translated from Latin to English in 1811 by a Swedish merchant named Carl Troilius, who introduced several errors that affected all subsequent tafl reconstructions.
Carl Troilius incorrectly stated that four attackers were always needed to capture the king. The original Sámi rules required only two attackers in most cases. This error made the defending side far too powerful and unbalanced every tafl variant reconstructed from the translation.
The World Tafl Federation was formed in August 2011, with Tim Millar as Chairman and Adam Bartley as Vice Chairman. It has held annual world hnefatafl championships since 2011, with participants growing from 8 players in the first year to 36 by 2025.
Tafl artifacts have been found across Northern Europe and beyond. A wooden board and horn gaming piece came from a ship burial at Gokstad in southeastern Norway. Twenty-two whalebone pieces were found in Orkney. Glass gaming pieces were recovered from the mound of Birka in Sweden and in northern Ukraine and Russia. A gaming board dated to the 8th century or earlier was excavated in 2018 at the site of the Scottish Monastery of Deer.