I WROTE THIS ARTICLE FOR KIRBY'S BLOG, 3++ IS THE NEW BLACK, AND WAITED FOR HIM TO POST IT THERE TO CROSS POST IT HERE.
To begin any discussion about tournament terrain, the first and most  important thing to do is read Games Workshop’s own commentary on terrain  for Warhammer 40,000.  You may or may not always like what GW does with  its company or rules, but we love and play this game for a reason … so  let’s see what they say about the game.
As a general rule in Warhammer 40,000, the more terrain, the better  the gaming experience.  If you use too little terrain, games will be  short and not very satisfactory, with too much advantage going to the  player who gets to shoot first.  For a balanced game, where close combat  troops have a chance to get into contact with the enemy without being  completely blown away in a couple of turns, we expect that about a  quarter of the total playing surface should have terrain on it.  The  assumption here is that if terrain pieces are roughly 12” by 12”, then  six or seven pieces are needed to fulfill the 25% recommendation on a  standard 6’x4’ table (of course these dimensions are approximate and  terrain features like woods should not be square, as irregular features  look much better!).
In your terrain collection there should be a good mixture of types.   An equal division between terrain which interferes with line of sight  and provides cover (Such as woods or ruins), terrain which provides  cover, but does not block line of sight (such as barricades, craters,  scrubland and low rubble), and terrain which blocks line of sight  completely (such as hills, rocky outcrops, buildings, etc.) makes for  good tactical play.  It is best to build your terrain collection with  this in mind, otherwise the game balance could be seriously affected.   Terrain that completely blocks line of sight is particularly important.   Too much of it and your ranged firepower will be seriously impaired  favoring assault troops; too little and the game will turn into a  shooting match, with very little movement or tactical choices.
Alright … so we have a couple of things to work with here; terrain that  obscures line of sight, terrain that doesn’t obscure line of sight, and  terrain that completely blocks line of sight.  We also know special  attention should be paid to terrain that does block line of sight  completely – not too much, not too little.
I actually would put your TYPICAL tournament terrain as “trees” and “low  hills” covering the same category as barricades, craters, etc., with  ruins and dense trees and taller hills covering the “interferes with  line of sight” component, and true LOS blocking buildings and much  taller hills being true line of sight blockers.  Contrary to what some  people will say, if your rhinos and chimeras and such cannot hide behind  a piece of terrain, it is not line of sight blocking terrain for  purposes of Warhammer 40,000 5th edition (A very vehicle heavy edition,  as we all know).  The same applies to monstrous creatures.  I’m not sure  if every LOS blocker should shield over-sized vehicles like Land  Raiders and Vendettas, but you should at least be able to hide your  transports and/or smaller vehicles to some point on the board.
Games Workshop hits on it themselves somewhat, but the biggest issue  with tournament balance and gameplay is the viability of alpha strike  armies … armies that by reserving when going 2nd, or deploying when  going 1st …. Are simply built to overpower an enemy starting with the  first turn of shooting.  When you do not play with enough terrain as a  general rule, you find more and more players that talk about these sorts  of armies as “overpowered” and in other ways inappropriate.  Good  examples of this are pure missile and razorback spamming “Razorwolf”  Space Wolf armies, typical “leafblower” styled long-ranged Imperial  Guard armies, Darklight and/or Venom spamming DE armies, and the like.   It should be no wonder that when you encounter players who use a full  GW-suggested quantity of terrain in every game, they’re a little  flabbergasted that these lists alone seem to garner so much ire from the  internet.  Now, do not mistake the notions of MSU and redundancy as  being where we are going here – there are plenty of lists that leverage  the tried and true strategy notions of redundancy and MSU, but do not  rely entirely on long range fire and alpha striking.
The caution goes in both directions here, however – you as much do not  want to encourage gunline alpha strikes BEYOND their intended balance,  as you do not want to encourage pure assault armies to go beyond their  intended balance.
What is the intended balance?  Well, GW with its beautiful 2 paragraphs  on terrain tell us more about their intent for the game and their desire  to actually have balance than they do almost anywhere else.  The  general point here is they WANT balance.
So how do we assist this in a tournament setting?
First thing’s first – we need to minimize the differences from table to  table.  While it is impossible for every table at a tournament to be  identical and equally fair (At least at a larger event) resource-wise …  and frankly excitement-wise … it IS possible for every table to have the  same basic terrain format.  For the NOVA, we’ve extensively playtested  and tournament-run with an “x” formation of larger terrain pieces, and a  couple of smaller items.  We want the terrain itself to cover about 25%  of the board, and be a good mix of types.  Here’s a sample chucked into  a board quarter marker on Vassal.

We need at least one piece that completely blocks line of sight … and if  one is where we’re going with that, it needs to probably go in the  center of the table.  “Centering” your main line of sight blocking  terrain accomplishes a couple of things very quickly.  First, an alpha  striking army needs to make the difficult decision of deploying “split”  into corners if it wants clear fire to all parts of an opposing army; if  it chooses to castle or deploy centered, it’s going to have to contend  with line of sight blockage.  This single piece of terrain alone is the  first BIG step in balancing out alpha strike long range vs. close combat  and/or short range styled army builds.  You do not want to go too far  here – if you place your large LOS-blocking or partially los-blocking  piece in the center, you need to leave the areas to the left and right  to it more wide open; this presents the tactical challenge to both  players of how to address crossing / preventing the crossing of the  board – center with cover and LOS blockage, or sides with openness but  division of forces / sacrifice of the mobility advantages the center  offers.  If you put los blocking pieces ACROSS the center at even  intervals, you’ve instantly harmed the balance of the game TOO much in  one direction – close combat armies, jump armies, etc., can all cross  the board in whatever capacity they wish … all choices are equally safe.
The next thing we need to do is place the remainder of our terrain for  TOURNAMENT BALANCE purposes.  It is reality that in a larger setting,  people rarely have the willingness to run around a long row of tables by  choosing the OTHER side of where they randomly wound up upon arriving  at their table assignment.  You do not want the entire flow and balance  of the game to fall upon the comfort or feasibility of where players are  in a row of tables, and their ability to lug their army all the way  around it.  For this reason, you want the terrain to generally be fair  for both players REGARDLESS of table side or deployment style.  Dawn of  War is less important to factor in here than Spearhead and Pitched  Battle.  To keep things square here, our 4 remaining larger pieces that  provide at least some LOS obscuring is to place one in each quarter of  the board, nominally around the center of the quarter.  This is the  final piece of the puzzle in encouraging games to be tactical, and  balanced regardless of pure firepower, in that it enables a player to  deploy covered if he/she so chooses.  This protects the player with  foresight from getting blown off the board or forced into unwilling  reserves simply off the “who goes first” dice roll, or the initiative  seize.  We’ve also offset them away from “lining up” with the larger LOS  Blocker in center, so if a closer range army wants to heavily utilize  these offset pieces for cover on deployment, they are going to have a  more difficult path across the board if they want to stay covered.   Choices, and the freedom to play without the terrain inhibiting or  helping you to an unfair degree, are what we’re going for here.
Finally, we’ve got a couple of small pieces to round out the 25% and  give the board tactical depth … the “safe” bet is to place them centered  along the long table edges, and aligned with the centerpiece.  You  don’t want these particular pieces to be too LOS-blockish … some is ok,  but mainly they should be lighter area terrain type items.
The result is a board that looks something like this for either Quarters or Pitched Battle deployments:
The most important catch with all this is to do what you can to  accomplish the MINIMUM first on all boards.  Acquiring and providing  roughly equivalent terrain across the length and breadth of a large  tournament is one of the most difficult and expensive prospects facing a  tournament organizer, but it is also one of the most important things  to the success of a Warhammer 40,000 event.  Even at the 2010 NOVA Open,  we had some boards that did not match the format above, and those were  often the cases where you heard about it from players … they felt the  boards in some capacity let down their playing experience.  While the  majority were quite good, our hope and plan this year is to ensure ALL  of our tables are up to the standards we set forth.
One way or another, the point here is the same point one really applies  anywhere in tournament preparation – analyze, think, playtest, and  litmus test all of the various components and notions of a tournament if  you are going to run one.  Do not hamfistedly throw together random  missions, do not simply scatter terrain randomly about every board, do  not print out your scoresheets the night before and flick a few copies  around the tables and suggest people “share.”  Apply attention to  detail, and an honest willingness to accept critique and use what you  can of it to make your event better (without sacrificing your vision or  fun).
Sallow me to add yet anotherREMINDER for the NOVA Open 2011 (
http://novaopen.com).   At this point, we still have about 35 spots left for our Warhammer  40,000 256-player 8-rounds-for-all GT.  Thousands in prizes and even  cash, nice little swag bags, and gamers from literally around the world  await the intrepid attendee, plus social outings and events in the heart  of the capital of the United States of America.  For questions or  input, you can reach me at 
mvbrandt@gmail.com or through the NOVA’s website (again, 
http://novaopen.com)  … hopefully this was a helpful guide to setting up your terrain at  home, or in a tournament setting, to the betterment of the game and a  more fun experience.
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