Shield Wall Fighting - how would you model it?

[Icelander]

Originally Posted by DanHoward

There are four main ways to gain an advantage over a shield wall:

Break up the formation with missile weapons.
Give the men in your shield wall spears that are longer than theirs.
Outflank them
Attack them with something so scary that some in the line will turn and flee (heavy cavalry, scythed chariots, elephants, etc)

The problem is that in current GURPS rules, a shield wall grants no advantages at all. There's no need to break up the formation because there are no rules that make it better to be in formation.

The OP is looking for rules that do make a formation superior to not being in formation, probably preferably accompanied by rules which cover the limitations of being in formation. Rules covering shoving and the press of multiple men against each other would also be favourities.

None of these exist. The current GURPS Mass Combat rules abstract such concerns away and the rules in the Basic Set are meant for individual combat or small squads of irregular combatants (i.e. adventuring bands). Shield walls, phalanxes, pikes and suchlike may be mentioned, but there are no solid rules for how they affect combat. That will have to await a happy time when someone is willing to write a book on military matters, warfare or something similar.