Best Terrain for blocking position?

[Colt Ward]

As the question asks, what is the best terrain to build or set a blocking position to stop an enemy advance- be it just mechs or combined arms?  Additionally, the attacker is unable or unwilling to play the air-mobile game and use a DS to cross the obstacle.

[Daryk]

Water isn't as much of an obstacle for 'mechs.

[Colt Ward]

A major river that is 150-180 meters (5 to 6 hexes) even if only a single depth is going to slow down most mechs since only a few (lights) will be able to jump across.  They are the same sort of rivers that halted movement in WWII.  If the defending side (b/c it sometimes is the case) goes from Depth 2 to Level 1 for a combined change of 3 levels its going to be harder to get out.  Basically if you can find the ideal or near ideal spot, which one is going to be best- keeping in mind that obstacles are best served with covering fire.

Finally, just like we have 'amphibious' APCs, they still prefer to put them across a bridge rather than swim it across b/c the risk calculations- a mech can always fall and breach.

[Weirdo]

Finding terrain that will stop a mech advance in its tracks and force it to take a narrow corridor will be pretty hard to find. We're talking extremely steep slopes, ultra-dense foliage, water that goes straight to crush depth right at the shoreline, that kind of stuff. Terrain that will slow them to a crawl and make them want to use your corridor? That's much easier. Terrain that will stop at least part of a combined-arms force is actually fairly easy to whip up, given most vees' difficulty with woods and often water of any kind.

Of course, there are ways to deal with such issues. Artillery, frag missiles, or even a couple Agromechs can open an unexpected path through woods, a couple bridgelayers can create ways to ford a river, and any force of company size or later can easily put out enough firepower to collapse a cliff face into a traversible slope even without wasting ammo.

Of course, performing such engineering under fire is another matter entirely...

[Colt Ward]

Sure, you can work around most things . . . it just becomes a trade off between time, equipment and distance.  For instance, will raids have all that equipment you mentioned?  Will most invasions even?  Kept trying to find the quote about how useless obstacles were without covering fire- either direct ranged fire or artillery- to keep engineers/sappers from working their way through obstacles.  Can your LRM Carriers open a lane through the minefield/trees before my artillery starts landing on them?

[Weirdo]

Such tactical challenges are where memorable scenarios come from.  :)

[Simon Landmine]

Water isn't as much of an obstacle for 'mechs.

And those darned hover-tanks just ignore it completely, treating it as a highway ...

(But, as Colt says, it'll slow the 'mechs down, and be a real pain for most non-hover ground vehicles. Especially if not all of the bridges at the primary crossing point are rated for the heavy tanks.)

And now I'm having ideas for some more MM terrain boards - possibly 4x4s this time. Thank you!

[Sartris]

A bridge over a large crevasse would be the most obnoxious position to attack. Only VTOLS and jumpers could get over and the defenders could blow the bridge as soon as it became obvious they couldn’t hold

[RifleMech]

I'm thinking mine the river bed and the river. That would really slow an advancing enemy down.

[monbvol]

I tend to agree rivers if wide enough actually seem to be the best.

Use your mechs with hands to drive some I-beams or tree stumps at an angle into the riverside as quick and dirty tank traps, toss in some mines if you have them, and set up your kill zones.

[Ursus Maior]

As the question asks, what is the best terrain to build or set a blocking position to stop an enemy advance- be it just mechs or combined arms?  Additionally, the attacker is unable or unwilling to play the air-mobile game and use a DS to cross the obstacle.

The question is a bit inconclusive or at least the examples are. An isthmus is an operational or strategic choke point, but on a small operation or on a tactical level, it might not hinder movement at all. A pass is usually a single road of passable terrain. That's a lot less space to maneuver in, similiar to your example of a river or a road through marshlands.

Whenever passable terrain is reduced to a single road, that's an excellent choke point. The rest is a question of the depth of the terrain. Sure, a river may be 150-180 meters wide, but a pass can be several kilometers up and down with hundreds of meters of height to overcome. And marshlands can stretch for hundreds of kilometers, e. g. Pinsk (or Pripet) Marshes in Belarus. A single river will hardly be wider than 1 or 2 kilometers, and 'Mechs that are underwater will be largely impervious to most attacks by enemy forces. So rivers are not much of an operational obstacle compared to wider areas that are impassable.

[AlphaMirage]

Forest or swamp to stop combined arms , tanks (especially those wicked little hovers) hate that kind of stuff but you could set up hardpoints along the way.  An Alacorn in a clearing with good LOS for example will wreck anyone's day.  This will break the enemy into smaller forces that are less able to support one another and you can take them apart piecemeal, sure mechs can jump but not all mechs can jump and if you hide a Hetzer or AC/20 field gun in the woods they are going to feel it.

[grimlock1]

Finding terrain that will stop a mech advance in its tracks and force it to take a narrow corridor will be pretty hard to find. We're talking extremely steep slopes, ultra-dense foliage, water that goes straight to crush depth right at the shoreline, that kind of stuff. Terrain that will slow them to a crawl and make them want to use your corridor? That's much easier. Terrain that will stop at least part of a combined-arms force is actually fairly easy to whip up, given most vees' difficulty with woods and often water of any kind.

Of course, there are ways to deal with such issues. Artillery, frag missiles, or even a couple Agromechs can open an unexpected path through woods, a couple bridgelayers can create ways to ford a river, and any force of company size or later can easily put out enough firepower to collapse a cliff face into a traversible slope even without wasting ammo.

Of course, performing such engineering under fire is another matter entirely...

There's a rule in Tac Ops for collapsing a cliff face?  Need to look that one up!


A 1 hex wide, 3 level deep canyon will stop everything but jumpers, VTOL and WIGEs.  Yeah, even a Urbanmech can hop across that, but all the non-jumpers will have to take the long way around. Or build a bridge. Or as Weirdo said, blast some ramps into the canyon.  That won't stop an advance cold, but it will certainly throw a wrench in the works. The longer the enemy sits there building a bridge or a ramp or whatever, that's more time for you to prepare.  Evacuate likely targets. Plant mines, bulldoze roads into rough terrain.


Something that would turn real evil, real fast would be a flooded city.  All the streets have 1 level... 1 depth... A mech standing at street level is waist deep. If you can control key lines of advance and shoot down the streets at mechs slogging through the water, TMMs start to go away.  PSRs from 20+ damage will be nerfed by being in water, but failing that roll after a breach will suck.   The jumpers will take to the rooftops. Shoot at the buildings.  They take fall damage, which may or may not be nerfed by the water, but that will generate breach rolls.

The other evil thing would be to mine, destroy or otherwise mess up the road running through a forest.  But also plant command detonated infernos around the perimeter. Wait until most of their force has moved off the roads into the cover of the woods and light the match.

[Colt Ward]

Not sure if you can collapse a cliff face per se, but you CAN 'lower' a hex's height.

[Weirdo]

Has TacOps taught you nothing? Of course there's a rule for that!

TacOps page 64 has the damage needed. 50 damage turns a sheer cliff into a normal slope. 200 damage turns an empty hex into a rough hex 1 Level shorter. This sounds like a lot of damage, but all the energy weapons of a decent-sized force should be able to manage that in a few turns. I don't recommend using melee attacks to try and supplement this unless you know this isn't the final turn of shooting at the hex: Landslides can hurt.

[Colt Ward]

What do they consider sheer?  Because the art on the current BT maps have a pretty definite face for a L2 change- even some of the L1s.  Yeah, the 200 pt hex change is what I was thinking of to be able to lower a facing.

[Simon Landmine]

Something that would turn real evil, real fast would be a flooded city.  All the streets have 1 level... 1 depth...

Ooh, I like it. I'd had ideas of a canal-city already. Might have a go at that.

What do they consider sheer?  Because the art on the current BT maps have a pretty definite face for a L2 change- even some of the L1s.  Yeah, the 200 pt hex change is what I was thinking of to be able to lower a facing.

IIRC, according to TacOps(?) 'sheer cliff' hex-edges have to be specifically defined, otherwise it's just a very steep slope. Can't reach the reference quite now, though.

[Weirdo]

What do they consider sheer?  Because the art on the current BT maps have a pretty definite face for a L2 change- even some of the L1s.  Yeah, the 200 pt hex change is what I was thinking of to be able to lower a facing.

To my knowledge, there are no published maps with sheer cliffs on them yet. It's the kind of thing that would be explicitly printed on the map.

[Colt Ward]

Sure, I just wonder what it looks like b/c I have not seen anything with that in MM when designing maps and most stuff is ported over.  Additionally, like I said the new maps artwork makes it look like a pretty defined 'edge' though a approximately 17-21 meter change in elevation in a relatively short space would be difficult to go up.  Though that is from experience looking at a topo map and then staring up (or down) and looking for a easier place to cross.

[grimlock1]

Ooh, I like it. I'd had ideas of a canal-city already. Might have a go at that.

IIRC, according to TacOps(?) 'sheer cliff' hex-edges have to be specifically defined, otherwise it's just a very steep slope. Can't reach the reference quite now, though.

Canal city would be bad, flooded city is worse because when the building collapses underneath you, you're back in the water.

[Kit deSummersville]

Water isn't as much of an obstacle for 'mechs.

I thought that one Masters and Minions fight and my dang Hellbringer never made it out of the water.

[Mohammed As`Zaman Bey]

  Channeling terrain varies with a player's methods of turning the channel into a kill zone. As per WW2 German doctrine, a channel's effectiveness is amplified by mining, a minefield multiplied by antitank guns, add layers of defenses, artillery, aero, dug-in infantry, etc., and you could replay the Battle of Hürtgen Forest or Kasserine Pass.

  A waterway not only slows advance but its very nature can make it a fine kill zone. Most land forces are fully prepared for a land battle, but very few remotely anticipate a fight in and under water. Submerged mines and LRM/SRM torpedoes from submerged launchers could wreak destruction on virtually helpless units, whose weapons are reduced in effectiveness or useless while submerged.

  Difficult terrain may only slow Mechs but an imaginative, determined defender could make crossing that terrain nigh impossible.

  From MM, "Battle on the Ice":

Round 1:
Movement Phase
-------------------

Warhammer WHM-6D (Pirates1) must make a piloting skill check while moving in hex 1003
(running & turning on pavement).
Needs 6 [5 (Base piloting skill) + 1 (running & turning on pavement)], rolls 5 : falls.
Warhammer WHM-6D (Pirates1) falls 0 level(s) into hex 1003   
 Warhammer WHM-6D (Pirates1) falls on its left side, suffering 7 damage.
        Warhammer WHM-6D (Pirates1) takes 5 damage to RT. 17 Armor remaining
        Warhammer WHM-6D (Pirates1) takes 2 damage to LT. 20 Armor remaining
Pilot of Warhammer WHM-6D (Pirates1) "Zamoyski" must roll 6 to avoid damage; rolls 6 : succeeds.
   Skids into hex 0904.
   Skids into hex 0804. (Note: This is a water hex)
    Warhammer WHM-6D (Pirates1) suffers 8 damage from the skid.
        Warhammer WHM-6D (Pirates1) takes 5 damage to RA. 17 Armor remaining
        Warhammer WHM-6D (Pirates1) takes 3 damage to LT. 17 Armor remaining
      Skid ends.

Round 4:
Warhammer WHM-6D (Pirates1) must make 1 piloting skill roll(s) (20+ damage).
The base target is 6 [5 (Base piloting skill) + 1 (20+ damage)].
    Roll #1, (20+ damage); needs 6, rolls 4 :  falls.
    Warhammer WHM-6D (Pirates1) falls on its right side, suffering 3 damage.
        Warhammer WHM-6D (Pirates1) takes 3 damage to RT. Armor destroyed,
<<<Warhammer WHM-6D RT BREACHED>>> <<<Warhammer WHM-6D CT BREACHED>>>
*** Warhammer WHM-6D (Pirates1) DESTROYED by hull breach! ***

Pilot of Warhammer WHM-6D (Pirates1) "Zamoyski" must roll 6 to avoid damage; rolls 4 : fails.
        Pilot of Warhammer WHM-6D (Pirates1) "Zamoyski" takes 1 damage.

[Daryk]

I thought that one Masters and Minions fight and my dang Hellbringer never made it out of the water.

That's why I said "as much of an obstacle" vice "not an obstacle"...

[Simon Landmine]

Sure, I just wonder what it looks like b/c I have not seen anything with that in MM when designing maps and most stuff is ported over.

I don't think MM supports sheer cliffs yet.

Canal city would be bad, flooded city is worse because when the building collapses underneath you, you're back in the water.

Ooh, that's a good point. Nasty! Hmmmmm ...

[grimlock1]

Submerged mines and LRM/SRM torpedoes from submerged launchers could wreak destruction on virtually helpless units, whose weapons are reduced in

Mines buried in the river bed?  Nasty.

Short of elevation changes that are greater than jump capacity, and the sea floor below crush depth, the only terrain that is "impassable" for mechs is Ultra-Heavy Woods or Ultra-Heavy Jungle.  Although it I'm reading right, it only takes a couple heavy PPC hits to knock it down to Heavy Woods. The best you can do is blast the woods/jungle down to Rough terrain.

[Colt Ward]

Not even really suggesting impassable terrain . . .

For me the whole point of the blocking position is simply that it covers the most passable terrain in a area forcing the enemy to try to traverse the difficult terrain which slows them down and/or bunches them up for covering fire while costing the enemy time.  Any obstacle or difficult terrain near a blocking position should be under observation and covered by direct or (better) indirect fire to cause the enemy damage along with time.  IMO it also allows a defender to use munitions that they might not otherwise typically put in play- for example, LRM launchers could be loaded with Swarm munitions to take advantage of enemy bunching up.  Of course it is a perfect deployment for artillery and mines because they compound the problem of terrain that is difficult to traverse- remember the maxim, the obvious path is always mined!

I think part of making a blocking position work would be having a AA deployment that keeps your opponent from using DS to engage in air mobile operations.

We do get a few instances in BTU of battle in these sort of places- Aiden's river crossing on Tukayyid, Tancred fighting Katherine's loyalists in the Drac March, Redburn & Delta Company ambushing a heavy company in a pass, and a few others but rarely does either side make full use of the terrain.

[Taber_Evans]

Water???   You do not have to hit the mech to breach it.  Use command fused depth charges.  Even improvised explosives will do the job.  Breach rolls for all units in the area of affect of standard mines and artillery rounds.  Its the concussive blast that forces the breach.

[Church14]

Hm. The thing is that I want the terrain to be beneficial to me without being so impossible that there isn’t a commander in existence actually dumb enough to attack it.

Hm. For reference, I will be defending the north side of the map.

Ideal for me?
1) I want a swamp or river running East-West that’s 5 hexes wide. Let the fastest jumpers go over and fight alone.
2) I want a tree line on the north side of the swamp. The tree line can have gaps, but I’d want those gaps to require at least one turn. That allows hover tanks through, but they either travel much slower to avoid PSR or risk eating trees on a failed roll.
3) A road running North-South. Ideally not going straight over the swamp/river so that mechs want to walk around the corner and not risk a slip when running. I want a place where I can have my pre-plotted artillery ready.

This isn’t the most impossible terrain. What it does is provide a lot of incentive for attackers to split their forces in such a way that I can reasonably focus down specific elements 1 at a time.

A lot of ideas listed are ones where my response to the challenge of attacking is to find a way around because attacking a force there is comically stupid.

[Mohammed As`Zaman Bey]

A lot of ideas listed are ones where my response to the challenge of attacking is to find a way around because attacking a force there is comically stupid.

  Look at the number of Tukayyid scenarios that are either ambushes or channeled attacks against determined defenses. So, why didn't Clan forces simply bypass suspected ambushes or use their DS lift to avoid known choke points? Actually, quite a few of the canon scenarios are based upon avoidable skirmishes that for one reason or another, the attacker decides against avoiding.

  Ambushes are ambushes -The attacker either has no clue of the actual defenses, severely underestimates their capacity or overestimates the capabilities of their own force. If the enemy is aware of the defenses and chooses another route, the deterrence is also a success, as I have also placed fake built-up positions and placed highly mobile forces in the path of attackers in order to force them to seek another path of travel, costing them time and creating opportunities for subsequent ambushes.

  Part of destroying and enemy is forcing them onto a predictable path of travel by eliminating viable alternatives. Another part of choosing a choke point is being aware of alternate routes, just in case the attacker is overly cautious, and either making them impassible or giving the attacker the mere illusion of a trap.

  For a while, facing Clan forces became easy, once their motivations were predictable. If a Clan forced wanted to fight my battlemechs, I'd force them to traverse land mines, dug-in infantry, emplaced vehicles and artillery -Then I would happily face the survivors.

[Church14]

  Look at the number of Tukayyid scenarios that are either ambushes or channeled attacks against determined defenses. So, why didn't Clan forced simply bypass suspected ambushes or use their DS lift to avoid known choke points? Actually, quite a few of the canon scenarios are based upon avoidable skirmishes that for one reason or another, the attacker decides against avoiding.

  Ambushes are ambushes -The attacker either has no clue of the actual defenses, severely underestimates their capacity or overestimates the capabilities of their own force. If the enemy is aware of the defenses and chooses another route, the deterrence is also a success, as I have also placed fake built-up positions and placed highly mobile forces in the path of attackers in order to force them to seek another path of travel, costing them time and creating opportunities for subsequent ambushes.

  Part of destroying and enemy is forcing them onto a predictable path of travel by eliminating viable alternatives. Another part of choosing a choke point is being aware of alternate routes, just in case the attacker is overly cautious, and either making them impassible or giving the attacker the mere illusion of a trap.

  For a while, facing Clan forces became easy, once their motivations were predictable. If a Clan forced wanted to fight my battlemechs, I'd force them to traverse land mines, dug-in infantry, emplaced vehicles and artillery -Then I would happily face the survivors.

Except that the approaches of the clans at Tukayyid are textbook examples of how to have a better armed force with better pilots get their asses handed to them through poor tactical and strategic choices. Banking on an enemy being cripplingly stupid isn’t a reliable long term bet.