Minden Games Retro Essential Houserules

AFV

Note: these rules are mostly about "soft" factors, humans rather than hardware. Being house rules they are highly opinionated, and not entirely essential.

Armor combat vs Ordnance and Infantry:

Instead of using the Armor Combat Table for Gun fire vs non-vehicle targets, use the Retro Infantry Fire Table. The caliber of the gun in mm in red (round down) in the top row (as in Squad Leader and ASL) determines the column to use. So a 75mm gun uses the "12/70" column. Pencil in the above number on your Retro IFT.
Apply TEM as leftward column shifts. So 75mm gun vs infantry in woods is the "8" column. Tank Leader DRM applies.
Trucks use the Armor Combat Table, Armor value = 0.

Comment: A Retro Stewart 37mm gun kills an entire squad on a 9 or less with 2 D6, 0-6 hexes, no modifiers. This is very unlike Squad leader. Now it fires on the IFT "2" column. Which is still deadlier than Squad Leader, since there is no "To Hit" roll. Same as JOSÉ LUIS VALLÉS

Group Vehicle Hesitation:

If a Tank Leader passes his Hesitation check, so do all adjacent friendly AFVs. If a Tank Leader fails his Hesitation check, so do all adjacent friendly AFVs. AFVs adjacent to a Tank Leader do not have separate Hesitation checks.

Comment: This avoid the Kung Fu movie effect where you have 6 tanks, but only one gets to attack each turn. Now a troop moves as a troop.
We also assume that an AFV causes hesitation only in its covered arc.

Group Vehicle Radio:

If a Tank Leader passes his "AFV without Radio" check, or has a radio, all adjacent friendly AFVs enjoy a -2 modifier on their individual "AFV without Radio" check. If a Tank Leader with no radio fails his "AFV without Radio" check, so do all adjacent friendly AFVs.
Comment: 'Do whatever the boss is doing' was a standing order for Soviet tanks.

2-Man Turrets

An AFV that has a turret, with a turret crew of less than 3 suffers a 2 column right shift on its first shot at any target. This does not apply to subsequent shots unless either party moves, or LOS is broken. This applies to (more or less) all light tanks, Brit heavies before Churchill, Brit Medium before Crusader, Soviet heavies before KV-1, Soviet Medium before T34/85. All Japanese and Italian tanks. German medium/heavies have 3-man turrets.
Comment: In a 2-man turret, the commander sits looking thru the gunsight and has a limited field of view. Or has his head out and is not at the gun station.

Combine MG and Gun:

If the target is within 10 hexes, add 4 to the Gun FP for one dice roll, never fire the AFV MGs separately. 10-20 hexes, add 2. Just to speed things up.

Partial Kill:

If the Armor Combat Table die roll is equal to or just 1 higher than needed for a Kill, roll a D6: 1-3= kill, 4-5 the vehicle must Flee in its next movement phase according to the Fleeing DRM rules but without the +3 DRM. 6=Immobilized.

Comment: The Fleeing vehicle has been damaged or stunned, so the crew fall back, risking Hesitation and a second hit.

Crew Exposed (CE)

CE counters may be placed or removed anytime during the owner’s Movement Phase only.

The CE counter adds an additional 2 column left shift advantage on the AFT, allows road movement rate, and use of any AA MG fitted. If an pivoting AFV is not CE, add an additional 2 column right shift disadvantage on the AFT.

The exposed crew may be fired at on the IFT with a +2 TEM (no other TEM factors apply). A Morale check fail removes the CE counter for the rest of the scenario. An IFT KIA result does not eliminate the vehicle, but the AFV may no longer fire. Passengers in an armored halftrack may not fire unless in a CE position.

Optional Rule: Soviet AFVs are never CE.

Infantry

A natural 6 always causes SMC/MMC Hesitation.
All Debris/Rubble is open for hesitation purposes only, not for fire (Norman Smith).

Smoke

OBA may be used to place smoke instead of the standard High Explosive fire. Merely place a smoke counter in all 7 hexes of the Blast Area. Smoke lasts 1 turn (remove at start of firing player's next fire phase).

A Gun/Mortar firing directly may fire smoke instead of other types of ammunition in its Fire Phase, smoke exponent = 5. A Gun/Mortar may only attempt to fire smoke once per scenario. Direct fire smoke automatically lands in the target hex, if within range and LOS.
AFV's firing smoke cannot fire their MGs first.
50-70mm Gun/Mortar: smoke lasts 1 complete turn (remove at start of firing player's next fire phase), 71-100mm 2 turns, >100mm 3 turns.

All smoke placement must be done at the very beginning of the fire phase before other units fire. All smoke counters, throw a D6, a 6 means no smoke in that hex (smoke exponent = 5).

See back of counter: s8 (2-7 = you got smoke, 8 = you got it but it was the last one, 9-11 = no more smoke try again with another ammo, 12 = malfunction).

"Canadian tankers quickly discovered that a squadron smoke shoot permitted the Sherman to attack: a line of smoke placed along the front of an enemy position allowed them to close quickly into effective kill range. "

"Tank Tactics, From Normandy to Lorraine," by Roman Jarymowycz, Chapter 13 "Who Killed Tiger": The Great Tank Scandal, page 265-266:

Retro essential but missing Rules

Retro "is a tactical, squad-level World War II combat variant rules set."
It is a simplified ruleset for Squad Leader / Advanced Squad Leader.
Much of the ruleset is missing rules are missing, and you apply rules from Squad Leader or Advanced Squad Leader.

Retro is not a complete ruleset, you fill in the gaps with Squad Leader or ASL.

So I would take this line from the Retro Introduction to be a rule:
 "If you are familiar with how Squad Leader is played, you will have no difficulty using this variant"

I would suggest:

1. If Retro mentions it, fill in vital gaps with the minimum amount of rules from SL or ASL.
2. If Retro doesn't mention it, use SL/ASL rules as an optional expansion to Retro.
3. If there is doubt about interpretation of a Retro rule, use whatever is closest to the way SL or ASL does it.

• "Line Of Sight" is mentioned, but Retro has no LOS rules at all. So use SL/ASL rules or a subset thereof.
• "Minefields" are not mentioned, so minefield rules from SL/ASL can be used, but I would consider this an "expansion" to the ruleset, not part of the basic game.
• Broken units and Close Combat are mentioned, but there is no Retro rule for broken units in Close Combat. Squad Leader eliminates them instantly, so we do that.

Here are some of the missing pieces:

(Retro Tanks cannot rotate their turret, so we adapt Squad Leader facing and pivoting)

AFVs:

1. Units with a covered arc (including Ordnance, Bunkers and AFVs) can cause Hesitation in their covered arc only.
2. Vehicle Hesitation uses front or side armor values, depending on facing.
3. Pivoting is not moving. You may pivot AFVs or Ordnance at no movement cost, during the movement phase only.
4. Turreted AFV Firing during Fire Phase after pivoting within hex during Movement Phase +1 Column shifts right on Armor Combat Table.
5. Non-Turreted AFV or Ordnance Firing during Fire Phase after pivoting within hex during Movement Phase +3 Column shifts right on Armor Combat Table.
6. There are no Multiple Hesitation Rolls for vehicles.
7. HEAT Gun Factor is caliber in cm round down. So 10 for 105mm. HEAT depletion is "H" on counter rear. H7 means your last HEAT round, >7 no HEAT available.
8. HE vs Vehicle: as per HEAT, but a if you score a "Kill" on the ACT, roll a D6: 1= kill, 2-4 the vehicle must Flee in its next movement phase according to the Fleeing DRM rules but without the +3 DRM. 5= immobilized. 6 = no effect. 

Comment: HE vs AFV, The Fleeing vehicle has been damaged or stunned, so the crew fall back, risking Hesitation and a second hit. This gives the SU-122 some chance against a PzKpfw IIIJ (50L) with just HE.

Squad Leader Radios:

ASL counters have a number, such as "8" on the front of the counter. Squad Leader counters, see table below. I would guess British Commonwealth and Japanese to be 7. Other nations as per Russian.

Infantry:

Rate of fire of machine guns: LMG=1, MMG=2, HMG=3.

Broken units in Close Combat are eliminated (SL 20.9)

Retro routing is one move only, until rallied or eliminated (clarification).

Broken units already in a building or woods hex may either stay in the target hex or make a once only rout to other cover (SL 13.46).

Allow Defensive fire groups (SL 16.5)

Heroes: If a non-wounded hero (1-4-9, 6MF) fails a MC it is wounded. If a wounded hero (1-3-8, 3MF) fails a MC it is eliminated.

Line Of Sight:

1. Use a ruler, center to center, only the drawing of the cover blocks LOS.
2. Multi-story Buildings, the firer decides which level the firing and target units are on.
3. Walls and hedges block visibility if neither party is adjacent to the wall, and neither has a height advantage in SL. Fire is allowed along a wall/hedge hexspine with TEM benefits.

Generally, you can use dice as 3D line of sight tools, 1 for a wooden building or wood, 2 for a multi-story building, and eyeball the line of sight, rather than complex rules.

Rally Phase:

"Only the player whose turn it is may conduct activity in this phase." 3rd Ed, missing from 4th.