My local GW store organised an Imperial Guard versus Tau mega battle and I dusted off my Cadian 271st to participate. I built up a modest 1400 point army with minimal wargear because I always forget to use it in big battles. My IG allies were Vostroyan mechanised on the far left, Cadians led by our overall commander Ursarkar Creed on my immediate left and a Cadian 27th Armoured Company on my right. I reckon we had about 10,000 points. Unfortunately the main Tau force, commanded by the organiser of the game, didn't show up. That left just two Tau armies to oppose us with approximately 6,000 points.
The initial plan was to play a cleanse variant, with the winner of each board section being decided by whoever had the most scoring units present. There was to be no deep strike, infiltrate, scout moves or any other complicated time consuming stuff. You can see the general deployment in the picture below (taken after both sides 1st turn).
An early theme was the targeting of the Tau Ethereal with our ordnance weapons. I think he survived a Basilisk, Demolisher and Leman Russ shot on the first turn alone! It quickly became apparent that no-one was taking the battle too seriously so we all ran our armies directly toward each other. Our shooting was absolutely abysmal. My entire 1400 point army, which included 3 missile launchers, 3 multilasers, 1 heavy bolter, 1 autocannon and two ordnance templates didn't kill a single enemy model (on one frag shot I rolled six partial hits and got none). The rest of our combined firepower dropped a Devilfish and routed a unit of Kroot and a Fire Warrior squad. Shocking.
The only saving grace was that the Tau shooting was just as bad, and most of our tanks survived the first turn. With the Armoured company on my right engaging the Mech Tau I swung most of my units into the centre to support Creed and our allied Inquisitors in their push forward. I used my Russ and Demolisher to advance the Stormtroopers and Ogryn and zoomed my Armoured Fist out to flame the central building. Of course, they fluffed their hits and were wiped out in return. My Conscripts lost three quarters of their members and two of my Sentinels got popped.
We got two more ordnance shots on the Ethereal but still he survived! As we severely outnumbered the Tau, we allowed them to use reserves, and they dropped several gun drone units behind our advancing lines. They also dropped a Vespid unit down next to my Command Squad, killing four Guardsmen. Kennell survived.
On the third turn we finally nailed the Ethereal and several Tau units ran. We continued our central push, and my two ordnance shots failed to kill a Tau Crisis suit but the Conscripts took him out with rapid firing lasguns! My Cadian allies wanted to charge into the Vespid with my assistance but I refused, reasoning that supporting fire would do more damage. Predictably I only killed two and my Guard allies were not happy. Still - they managed to hang on and win in the following assault phase. I lost my last Sentinel and the Demolisher to return fire, while my Ogryns were decimated.
We had ran out of time so I had one final survey of the battlefield. The Vostroyans had taken heavy casualties but had held the left flank. The two mech forces on the right had fought each other to a standstill. Vicious short range firefights had broken out in the centre but we had Creed and Kell and our Inquisitor and retinue all in combat.
It was a good game - a bit ragged around the edges but tremendous fun. I'd love to do it again sometime.