If you were looking for the book, see Thud!
Thud is a board game based on the earlier dwarfish game of Hnaflbaflsniflwhifltafl. It is played mainly by Dwarfs and Trolls, although it does have devoted human players as well. In a game of Thud, the Dwarfs' side has a natural advantage and will inevitably win against an unskilled player. A careful player can achieve victory for the Trolls, however. A match therefore consists of two games with the players alternating sides. According to Reacher Gilt, a well-played game of Thud can reveal the weaknesses of one's opponent. According to Lord Vetinari, the goal of the game should be to discover one's own weaknesses. Mr Shine hopes that encouraging Dwarfs and Trolls to play Thud will promote peace between the two by providing an outlet for replaying the Battle of Koom Valley in miniature - and bloodlessly. Greater background information is given in Thud-A Historical Perspective.
The game itself echos the game played by Vikings and Anglo-Saxons "Hnefatafl"- which literally means "Kings Table". Hnefatafl echos go beyond just the name. Like 'Thud' it is unusual in that it is an 'asymmetrical' game - each side has different forces and different objectives (unlike, say, Chess). The defending side is trying to get the King to safety and escape on a corner square, while the besiegers/attackers are trying to either capture the king, or position their forces so his escape is impossible. Making Kings safe is of course a recurring theme in The Fifth Elephant and Thud!.
The dwarven pieces on the 1st edition front cover echo the 'Lewis' chess set, often used as an inspiration for modern reproductions, as it is the only known set of a Dark Age board game. This, along with the game, reinforces the 'pop-viking' imagery Pratchett uses for dwarfs. In 2002 (on Roundworld) the game Thud was created by Trevor Truran.
- The thirty-two dwarfs are arranged around the edge of the octagonal board, while the eight trolls are placed around the Thud-stone in the middle. The dwarf side goes first.
- The dwarfs can go any number of squares in any direction, including diagonals. The trolls, however, can only move one square in any direction.
- If a troll moves into a space next to a dwarf it can capture it. It has to move, however- it cannot take it while standing still. It can take any number of dwarfs with one move.
- If a dwarf is next to a troll and it has not been captured, it can capture the troll. However, what mostly happens is that the dwarfs are arranged into a huddle, and the front dwarf is 'hurled' by the back one to capture the troll. The number of squares it can be hurled is dictated by the number of dwarfs in the line. Trolls can also do this.
- The game ends when no more captures can be made. The pieces that still remain are given points- four points for an uncaptured troll and one for an uncaptured dwarf- and the players recommence, playing on the opposite side. The player with the most points wins.
There is also a another way that the game can be played called Koom Valley Thud, with new rules.
19/12/12: an episode of popular archaeological show Time Team aired on British TV, in which an Anglo-Saxon game looking very much like Thud was briefly displayed and described.