The background is that an Imperialist/Swabian army under Maximillian I has advanced into the Umbrail Pass to assert Habsburg rights (and to secure a route for dropping future Imperial armies into Italy!), and, knowing that a Swiss army (the most vaunted infantry in Europe at the time) was en route, the Imperialists constructed a letzi, a type of earthwork particularly well suited to defending mountain passes (and which would not quite look like mine). The Imperialists assumed that when the Swiss arrived a drawn-out siege-type affair would follow, so the letzi was "thinly defended", with reserve of infantry in the rear, and the Imperial gendarme heavy cavalry even further in the back. However, Benedict Fontana, the Swiss commander, decided to immediately storm the letzi instead.
(Above: starting positions. At the top you can see the Swiss, then the letzi defended mostly by Imperial arquebusiers, then the Imperial infantry reserves, and at the bottom the Imperial Gendarmes in far reserve)
The Swiss have 12 units and the Imperialists 16, although both math out to 56 points of Lion Rampant forces. The letzi is defended by two pike units and seven arquebusiers (bidowers in LR). The Imperial infantry reserve is two units of doppelsoldners (fierce foot) and another pike block. The second reserve line is four Gendarme units (mounted men at arms). The Swiss have four units of elite pikes (defend on 2+ in close order!), two units of halberdiers (fierce foot), four units of elite arquebusiers (bidowers who do not skirmish with the -1 to shoot), and two light cannon.
(Above: Imperialists defending the letzi)
(Above: the Swiss)
(Above: the Swiss advance, while some Imperial arquebusiers take heavy casualties form Swiss fire)
The Swiss went first and instead of a straight on assault decided to focus on the left end of the letzi. The two pike units and one halberd unit from the Swiss right thus formed a sort of second wave behind the Swiss left. The arquebusier units from the Swiss right piled into a wooded area and the mountain slopes to create diversionary fire - however a very good opening round of shooting by the Imperials beat these Swiss up as early as turn 2. The Imperial reserve infantry shifted to its right to meet the oncoming massed Swiss assault [retrospectively, the Imperial reserves should not have been allowed to try ordered activations for the first three turns to represent the element of surprise gained by the Swiss]. Shooting on the Imperial right was ineffective and the first unit of halberdiers came on fast, and stormed the letzi, dislodging a unit of arquebusiers. They were counter-attacked by doppelsoldners and destroyed.
(Above: Swiss halberdiers successfully breach the Letzi)
(Above: the Swiss halberdiers have been destroyed but a second halberd unit attacks the Imperial pikes while the Swiss pikes close in)
However, the turn after that the Swiss pikes assaulted and dispatched the weakened doppelsoldners and entered the earthworks, followed quickly by a second pike unit – at this point the Imperial arquebusiers were falling back to make way for counterattacks by the reserves, and the Imperial Gendarmes had maneuvered up into striking distance of the earthwork as well.
(Above: Swiss pikes enter the earthwork)
The Swiss formed up in close order and there were some interesting pike vs. cavalry fights that usually saw the Gendarmes take the worse of it, but by this time, given the expensive nature of their pikes & arquebus units, the Swiss were on the verge of complete army collapse – the Imperials by comparison had a lot of damaged units but most had drawn back from where the combat was. In the end, an unfortunate roll on a Swiss pike block morale check threw the game to the Imperials ("O Fortuna!").
(Above: Imperial reserves closing in)
I'm making the game sound a little one sided but the Swiss were definitely on a roll early on, and if I ran it again, I would not allow the Imperial reserves to start activations until round 3, as noted above. The earthworks were not a "game killer" for the Swiss (i.e. impossible to assault), partially because the halberdiers were great at punching an opening in them for the pikes to follow up into, and partially because I set the scenario to have the earthwork mostly defended by weak IMperial arquebusier units initially. The game had some nice dramatic "movie-feeling" moments to it as well, what with the Swiss breaking through the earthworks only to be faced by the approaching Imperial reserves.