Hills, Line of Sight (LOS), Height Advantage (HA), and a little bit on “reverse slope defense”. Starter Kit Example #2 from the rulebook. In an attempt to help out new and existing Starter Kit players I’m going to work through every example from the ASL Starter Kit rulebook. These snapshots are mere summaries/examples and are NOT meant as exhaustive replacements for reading the relevant rule sections.

You can download the full Advanced Squad Leader Starter Kit rules (which includes all rules for SK #1 through SK #4) at this link!


Hills in Starter Kit are a simplified version of those found in full ASL. Where that system has multiple levels from level 0 (including negative levels), SK only has level one hills. That simplifies them greatly, but also makes the concept of elevation and LOS easy to grasp.

ASL Map Spotlight: Operation Watchtower - Edson's Ridge
Edson’s Ridge, Guadalcanal

Hills (and buildings, and any other obstacle) in the ASL system are abstracted as “blocks” of terrain. When visualizing the 2D boards as 3D images in your head, picture the ASL world to be built of large Lego blocks. Normally hills in ASL don’t have the contours or undulations you see in real terrain, instead they are simplified as “steps” in the rules.

To illustrate this take a look at this old image from the original Squad Leader rulebook that I’ve simplified for SK purposes.

Squad Leader Line of Sight
Squad Leader Line of Sight

Notice the hill is represented by a step. In the SK rules if a LOS doesn’t cross a crest line before it exits a hex there’s no LOS to a lower-level hex (3.2.1). Barring other same-level obstacles all Level 1 hexes have a LOS to all other Level 1 hexes, just like (barring other same-level obstacles) all Level 0 hexes have a LOS to all other Level 0 hexes. That’s it! So in the above image:

  • hex 5 has a LOS only to hex 6, it does not have LOS to any lower level hex because the LOS doesn’t cross a crest line before it exits the hex
  • hex 6 has a LOS to hexes 5, 7, 8, 9, 10, 11 and 12 (LOS to 13 is blocked by the building)

LOS reciprocity applies.

Let’s look at this more detailed LOS example on Starter Kit board v. The American 6-6-6 squad in vK6 has a LOS to all the green hexes, and no LOS to the red hexes.

Starter Kit LOS Example #1
Starter Kit LOS Example #1

Note that the unit can see all the other Level 1 hill hexes, even across the orchard hexes in D4/E4/F3 which have the same height equivalent as a hill so the squad can see right over them. Also, note that the squad can see the Level 0 (Ground Level) hexes surrounding it because the LOS to those hexes crosses a Crest Line as it exits the unit’s hex. It can see over the “lip” (crest) of the hill. If it were back from the “lip” it would not be able to see over it. See LOS Example #2.

Further, note that the grain doesn’t obstruct the 6-6-6’s LOS nor does it even act as a hindrance because it’s at a higher elevation. But, the brush hexes in C3/D2 would still cause a hindrance to LOS in B2/C2 because it’s at the same level as the squad.

Let’s look at another example:

Starter Kit LOS Example #2
Starter Kit LOS Example #2

In LOS Example #2 the American unit is in vJ4, in the center of the hill, is completely surrounded by other Level 1 hill hexes. This would be considered a “reverse slope” position. The unit has no LOS to any other hexes except all other Level 1 hexes (in green). It’s too far away to see over any of the “lips” (crest lines) of the hills, thus it cannot see any lower-level hexes because any LOS traced out of vJ4 doesn’t cross a crest line before exiting the hex.

There are more LOS examples at the bottom of the page.

Height Advantage

Crest lines can be used to protect your units using a special TEM called “Height Advantage”. This HA only applies if the unit can claim no other TEM in the hex and if any incoming (non-mortar) fire from a lower elevation doesn’t intersect the hexspine crossed when moving into the hex with a crest line.

Starter Kit Height Advantage
Height Advantage Example

In this example German squad A moves into vK6. If the American unit fired on it that German squad would get +1 HA, thus negating FFMO. So the final attack on it would be 6 FP +0 DRM (-1 FFNAM, +1 HA). If the German squad was in vJ5 and move into vK6 the same would apply. A unit need not cross a crest line to be eligible for HA TEM.

If German squad B moves into vK5 it would not be eligible for HA TEM because the fire attack from the American unit would intersect the hexside being crossed as it entered a crest line hex.

HA TEM can also protect routing units from Interdiction in the same manner if the +1 HA can be applied in any hex where an Interdiction LOS enters.

Edson’s Ridge, Guadalcanal

Reverse Slope Tactics

“Reverse slope” is (typically) a defensive tactic involving positioning units in a hex that is blind to lower-level LOS. This approach obstructs the attacking force’s view of the defenders and diminishes the impact of their distance-based weaponry, like tanks and artillery.

In executing a reverse slope defense, the squad leader arranges the main defensive formations behind the crest of a landform. This natural barrier conceals them from the adversary’s direct observation and fire. This method can be adopted wholly or partially by the defense and is particularly effective for smaller-scale operations, typically at the battalion level or lower

Reverse Slope Military Tactics
Reverse Slope Military Tactics

Hills and crest lines can be used to simulate reverse slope defenses, and it’s advantageous to use this tactic in two situations:

    1. When no other terrain (other than HA) is available in a crest line hex, such as a building or woods (or in full ASL trenches/foxholes).
    2. Typically when you’re on the defensive and it’s your opponent’s DFPh. Beforehand, you can Assault Move away from a crest line hex and out of the LOS of lower-level enemy units so they can’t defensive fire on your unit(s). In the Advance Phase move back to the crest line hex to cover any enemy movement during their next turn. This ASL tactic is called “skulking”, and it’s a tried and true (and legal!) tactic.
Starter Kit Reverse Slope Tactics
Starter Kit Reverse Slope Tactics

Let’s tweak Example #2 and add a German 4-6-7 in hex vM7 who has the bright idea to assault the hill. Neither unit can see each other at this point, but they soon will. The Germans move out and expend 1 MF to enter vL6 then 2 MF (for 3 MF total) to cross the crest line into vK6. At that point, the American 6-6-6 can Defensive First Fire on it with 6 FP -2 DRM (no assault movement). Note, that the German unit does not get HA TEM because the fire did not originate from a lower elevation. The American unit could then SFF on the Germans because they spent 2 MF in hex vK6.

This is the beauty of reverse slope tactics. It makes attackers think twice about taking the high ground and paying for it when they do.

Historical Examples of Reverse Slope Tactics

Following the American paratroopers’ successful seizure of Carentan, German military units, comprising the 17th SS Panzergrenadier Division and the 6th Fallschirmjäger Regiment, launched a counteroffensive on June 13, 1944, aiming to retake the strategically crucial town. The U.S. 101st Airborne Division’s 502nd and 506th Parachute Infantry Regiments confronted the German advance to the southwest of Carentan in what became known as the Battle of Bloody Gulch.

The landscape provided a tactical advantage for the Americans, who implemented a reverse slope defense strategy. Positioned along the hedgerows at Hill 30’s base, three companies from the 506th PIR prepared for the confrontation. Despite being outnumbered and under heavy fire from tanks and assault guns, the Americans utilized the hill’s reverse slope to concentrate their firepower effectively on the advancing Germans. Their strategic position allowed them to withstand the assault until support arrived from the U.S. 2nd Armored Division.

The tactic of reverse slope defense was also favored by the Japanese forces during the Pacific island campaigns. The overwhelming naval artillery support of the American forces led the Japanese to adopt positions on the reverse slopes, enabling them to hold off until they could engage the American soldiers at a closer range.

Additional LOS Examples

Below are two additional examples showing how hills and LOS work.

Starter Kit LOS Example #3
Starter Kit LOS Example #3

LOS Example #3 is fairly simple, showing that the American unit can only see some of the crest line hexes of the two hills in front of it. If, theoretically, the building (vL7) had an upstairs Level 1 and the American unit occupied it, it would have LOS to all hill hexes, but would still not have LOS to any of the hexes behind the hills.

Starter Kit LOS Example #4
Starter Kit LOS Example #4

One important thing to notice from LOS Example #4 is the unit cannot see the hill behind the in-season orchards in hexes D4/E4/F3. If the orchards were out of season the squad would have a LOS (with hindrance) to the frontal hexes of the hill that have crest lines (C4/D3/E3/F2), but none of the other hill hexes behind those.

That’s all for now!

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Neal Ulen
Neal is a retired engineer/researcher who first played Squad Leader back in the late '70s. While getting re-acquainted with ASL after retiring, he took it as an opportunity to create VASL, Boot Camp, and AAR tutorials to help new and returning players. He lurks in the PWN.


  1. I know starter kit rules try to be minimalistic but your paragraph just below the old Squad Leader image plus the los example images just made hills click for me. I think I’m ready to try a secnario with hills now!



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