A Demonstration of Ard Ri
Sometimes you'll see a hnefatafl game called Ard Ri. It's mentioned on numerous web pages (including Wikipedia), it's sold in sets, it's playable on line, and there are even Twelve Hnefatafl Games for Your Mobile Phone: Ard Ri Tactics dedicated to the game. Which is very odd, as the game is unplayable.
Ard Ri has a number of guises, but all have the game played on a 7x7 board with 25 pieces: a king and eight defenders against sixteen attackers. These are numbers more usually associated with a 9x9 board, and crowding them onto a 7x7 board leaves little room for manoeuvre.
If Ard Ri were to adopt the usual rules of hnefatafl, with the pieces moving like rooks, the game would go something like the partial match presented here. In this example the attackers move first, but even if the defenders have the first move, they will be slaughtered by the attacking horde in much the same way.
As you can see from the diagram at move 4, the defenders are almost completely surrounded. As soon as the piece on C3 makes the only move available to it, it will be captured along with the defenders on C4 and D3, leaving the king and the remaining defender completely surrounded. The defenders may delay this by moving the king D4-D5 instead, but defeat is certain.
Some people invent a solution to this by allowing pieces to move only to adjacent squares. But this hampers the defenders about as much as it hampers the attackers. The result ends up the same, but takes a bit longer. It seems that putting too many pieces on a small board favours the attackers, just as putting too few favours the defenders.
It's for this reason that you generally won't see me mention Ard Ri on this site without derision.
1. C1-C2 E3-F3 2. E1-E3xF3 E5-E6 3. G5-E5xE6 C5-C6 4. A5-C5xC6/D5 ...