Fidchell, Brandubh, Hnefatafl, Ard Rí, and High King are all variants of a similar board game type, with individual rules varying from region to region, and sometimes village to village. Fidchell-type games increase in popularity the further North one travels, though before the great collapse "High King" was among the most popular board games of the Old Kingdom.
Common Characteristics
Fichell-games take place on a square board divided into smaller squares, with one player as the Defender, and the other as the Attacker. The attacker usually has twice as many warrior pieces as the Defender, though one of the defender's warrior pieces is a special piece called the High King. The High King piece is differentiated from the other warrior pieces by being taller, and usually more elaborately carved than the others.
The object of the game is for the defender to either push back the assault, or find a way for the High King to escape the battlefield, by moving the High King from its central starting position to one of the four corners of the board. This is no easy task, as the defending player starts out surrounded, and as previously mentioned, outnumbered two to one.
Variant Rules
Most Fidchell variants change either the size of the board, the ratio of attackers to defenders, or the capabilities of the high King. Smaller boards have less pieces, and typically offer quicker games.
The greatest amount of variation appears among the Northern clans, where each clan prides itself on its own particular version of Fidchell. Among certain clans, it transforms into a five person game, with four players as the attacker (one on each side) and the fifth as the defender. Another variant is that of the "last stand" variety, where the intent is not to escape, but to determine how many of your opponents pieces the defender can take down before the High King falls, often with additional reinforcements for the attacker every dozen turns or so.
That... kinda reminds me how a game i think i saw, regarding the "surrounded" thing. Nice image by the way! Is it inspired of a real game sold ? I don't know the name. Would you be eager to share it if it does ? :) Happy SummerCamp ! :D
Sorry for not replying earlier - they are all variants of Tafl games: https://en.wikipedia.org/wiki/Tafl_games The rules are mostly reconstructed, so they vary greatly in number of pieces/objectives, but all follow the same basic format. Hnefatafl is the best term to search if you're looking to pick up a copy of the game for yourself!