In his Austria-Hungary post, Larry gave us a few rules for tanks in combat. Here’s my interpretation of how they would work in battle from what we know:
On a turn after turn 4, Britain has purchased a tank and gotten it to a contested territory on the western front where it joins 5 British infantry and 2 British artillery who are facing 6 German infantry and 2 German artillery. Britain decides to test its new weapon in battle and sends its troops over the top to storm the German lines. The battle board is loaded as follows:
Britain (attacker)
5 dice are put in the infantry box (2 or less)
2 dice are put in the artillery box (3 or less)
1 die is put in the tank box (2 or less or 1, depending on how you read Larry’s A-H post)
Then, the tank and one infantry are promoted to the “With Artillery Support” box to roll at 3 or less (my guess is that, as in other A&A games, one artillery can only promote one other unit).
So, Britain will roll 4 dice at 3 or less (artillery + promoted infantry and tank) and 3 dice at 2 or less.
Germany (defender)
6 dice are put in the infantry box with the machine gun icon (3 or less)
2 dice are put in the artillery box (3 or less)
So, Germany will roll 8 dice at 3 or less.
Britain rolls its dice and gets 2 hits - the tank arrives on the western front with a whimper.
Germany, in a stout defense of its well built trenches, rolls five 5 hits.
Casualty allocation (done in turn, one unit at a time, starting with the attacker, but summarized below):
Germany allocates Britain’s two hits by removing 2 infantry pieces, leaving them with 4 infantry and 2 artillery.
Thanks to the British tank, the 5 German hits are reduced to 4 and Britain decides to loose 3 infantry and 1 artillery (Haig demands the tank be saved for a future assault), leaving them with 2 infantry, 1 artillery, and 1 tank.
The territory remains contested.
Nightmare Scenario:
The goddess Fortuna smiles on the Germans and they roll an unbelievable 8 hits!
The British tank reduces the 8 hits to 7, but Britain is forced to remove 4 infantry, 2 artillery, and its tank, because they must have at least 1 infantry unit.
In my imagination, the territory also included French units, but Larry has been pretty quiet so far on multinational forces, but my current assumption is that, as in other A&A games, they may defend together, but may not attack together.