Grid-Based SciFi Rules

These science fiction rules use a 6 inch grid for movement and shooting ranges. Although this can be adjusted for table top and model size. I use 28mm models and a 6 foot by 4 foot gridded playing area.

For those who do not like using a grid, you can translate a square to 6 inches for measurement or another measure to suit your models and tabletop space.

Two single model non-troop units (vehicle and monstrous creature) and troop unit of 5 figures


A unit size is normally 3-5 figures to represent a troop unit and 1 figure for a non-troop unit. Non-troop units generally represent a vehicle or monstrous creature.

Typically for a reasonable game you will require 8 to 12 units.

Only one unit can occupy a square except where one unit is a flyer.

All units have a 360 degree field of fire.

Sequence of Play

The game uses an IGO-UGO approach with players taking turns to activate all of their units.

After selecting the unit to activate, a player rolls between 1-3 activation D6 depending on the quality of unit:
  • Low quality units (Robots and Hordes) roll 1D6, but can roll 2D6 if they are adjacent to a leader.
  • Medium quality (Veteran) units roll 2D6
  • High quality (Elite) units, units with a hero, or units with a leader roll 3D6

Any odd scoring D6 allows a unit to make a move, go into overwatch, or unpin. Where multiple odd scores are rolled a unit may move multiple times.

All movement must end when a unit enters a terrain feature, unless they are a type of unit that ignores terrain (e.g. hoverer, fleet, or flyer units).

A Tyranid unit (low quality) rolls 2D6 because it is adjacent to a Warrior leader unit. If it were not next to a leader it would have rolled 1 D6. The 2 odd scoring D6 will allow it to move twice through terrain as it is has fleet properties and ignores terrain.
An even scoring D6 allows a unit to perform an attack action, or go into overwatch. Once a unit performs one of these activities it cannot perform any more actions during the players turn. 

A troop unit with two even scores can still only attack once, but can use both even scores to give them an advantage when attacking an enemy unit.

Non-troop units are able to attack two units when two even scores are rolled.

An Imperial tank has rolled 2 even activation D6. It can make an intense fire attack on 1 unit or 2  single attacks against both Tyranid units.
Once a player has activated all the units they want. The second player then proceeds to activate the opposing army units. This IGO-UGO approach continues until the end of the game, which can be a set number of turns or when set scenario victory conditions are met.


Actions are how a player’s units move, attack, unpin and go into overwatch.

For each odd D6 a player’s unit can:
  • Make a move
  • Use 2 or more actions to make a corresponding number of moves
  • Unpin after taking cover
  • Go into overwatch (end unit activation).
For each even D6 a player’s unit can:
  • Attack a unit within range (end unit activation)
  • Use 2 actions for an intense attack (end unit activation)
  • Non-troop units use 2 actions to make two attacks with separate weapons on different targets (end unit activation)
  • Go into overwatch (end unit activation).
A unit with an odd and even action D6’s can choose to move and make an attack. It cannot attack and move because an attack is a “last unit activation” and the unit’s action cease when taking one of these types of actions.

Units cease taking actions once they engage in an attack or have gone into overwatch.

A Space Marine unit prepares to attack some marauding Orks with intense shooting after rolling 2 even activation D6.


Leaders are important when a player's force has low quality units, as they allow an adjacent unit to roll 2D6 for actions.

They are able to activate any adjacent units either before moving and later where they have moved to adjacent to another unit.

A Necron leader with bodyguard.

Heroes and Henchmen

A hero or henchman in a unit elevates that unit to be elite and roll 3 activation D6. They also ignore moral for troop units.

A hero of the Imperium leads his squad and allows them to roll 3 activation D6.


When a unit is activated to move, it may move all or some of its movement allowance. 
  • A normal unit moves 1 square.
  • A swift unit moves up to 2 squares.
  • A fast unit moves up to 3 squares.
  • A flyer unit move is 4 squares.
Any unit moving into or out of a terrain feature can only move one square during a turn.
Skimmer, hover, fleet and flyer type units ignore terrain restrictions.

Assault troops with jetpacks can ignore the terrain and move 2 squares as part of their move activation. They will also be able to attack or go to overwatch with the even D6 activation.


Terrain features in most cases provide varying degrees of cover to units.
Units must end their movement upon entering terrain, unless they are a flyer, hoverer or fleet.
  • Buildings - blocks line of sight and provide troops with cover value of 4 if they use the take-cover rule.
  • Rough Terrain - provide troops with cover value of 4 against shooting attacks if they use the take-cover rule. Does not block line of sight.
  • Rocks and Trees - blocks line of sight and provide troops with cover value of 4 against shooting attack if they use the take-cover rule.
Squares with high buildings or hills offer units positioned within them an observation advantage and they are able to re-roll one or more of their activation D6.

An example of rough terrain. The terrain feature is placed in the centre of the 4 squares representing rough terrain. This way it does not crowd the squares with terrain, making it easy to move and place figures in the squares.


Units can attack another unit providing they are within range and line of sight.
  1. The attacking unit selects the weapon type best suited for the attack from their weapon selection. This represents the primary weapon used in the attack. 
  2. Roll the number of dice for the attack dependent upon the primary weapon and type of target. Add an additional D6 for intense fire.
  3. Select the highest scoring D6
  4. Subtract the units armour value from the score. Any remaining value is the number of hits a unit has taken. 
  5. Remove models from troop units, or place damage markers on non-troop units.
When an attack is declared the defending unit can, if in a terrain square, choose to take cover and use the terrain cover value rather than it’s armour value. This is particularly useful if a unit is lightly armoured.

An Oak unit uses its missile launcher (2D6) to attack a Space Marine unit who wisely take advantage of being in cover. Orks roll a 5 and 2. Using the highest score 5 minus the cover value 4 - causes 1 Space Maine casualty and a pinned unit.

Line of Sight

Line of sight must be traced from an attacking unit to the target unit which is within range. To assess whether a unit can be seen us a stick to determine a unit may see another unit.

Units positioned on hills or occupying multi-level buildings can have a line of sight over all units.

The Space Marines the building can be seen by the nearer Tau vehicle, but not the Battlesuit behind because the angle is too tight. The tightest line of sight angle is like the chess Rook move - two up and one across.

Troop Units

Troop units are represented by more than one model figure on the tabletop, which are removed as the unit takes hits.

All units have an armour factor based on their armour and strength which is subtracted from the highest attacking D6 to determine the number of casualties.
  • Lightly armoured or low strength - 2
  • Fully armoured or medium strength - 3
  • Heavy armour or high strength - 4
Troop units are subject to moral unless commanded by a hero or leader. When taking casualties if multiple figures are removed as hits from a single attack, then the unit’s unit is pinned.

A lightly armoured Tyranid unit, medium strength Ork unit, and heavily armoured Terminator unit

Non-Troop Units

Non-troop units represent tanks and monstrous creatures on the tabletop. They are always represented by a single model.

Non-troop units with multiple weapons and supporting fire systems may attack twice, providing the attacks are be on different units.

Damage markers are used to track hits. The number of hits a unit can take is dependent upon the strength and size of the tank or creature:
  • Light - eliminated after taking 1 hits
  • Medium - eliminated after taking 2 hits
  • Heavy - eliminated after taking 3 hits
  • Very Heavy - eliminated after taking 3 hits
Non-troop units have an armour factor of 5 and are only hit on a score of 6. However, if their armour factor is equalled with a 5, they are shaken or sustained some minor damage. Mark the unit as pinned.

If a non-troop unit is pinned a second time, then it sustains a hit.

A light Space Marine jet-bike, medium Ork Killa-Kan, heavy Imperial Chimera, and very heavy Necron Monolith

Weapon Types

A unit may have more than one type of weapon and can choose the most appropriate weapon for an attack providing it has the range.
  • Close Combat Weapons (pistols, claws, talons, etc) roll an 2D6 when attacking troop units.
  • Flamers (including toxic and acid weapons) roll 1D6 when attacking troop units or non-troop units. Target units cannot use take-cover option.
  • Power Weapons (e.g. Laser, Plasma, Melta, Powerfist weapons) roll 2D6 when attacking non-troop units and 1D6 attacking troop units.
  • Blast weapons (e.g. missile launchers, grenades, etc) roll 2D6 when attacking troops unit and 1D6 attacking non-troop units.
  • Large Blast weapons (eg basilisk) roll 2D6 when attacking any units.
  • Assault weapons (eg boltgun, laser rifle, assault gun, etc) roll 1D6 when attacking troop units.
  • Support weapons (eg heavy bolter, assault cannon) roll 2D6 when attacking troop units.
  • Snipers roll 1D6 when attacking troop units but increase range by 1 square.
Weapon ranges can vary from 1 square to 3 squares. The rule-of-thumb is:
  • All close combat and flamer weapons have a range of 1 square
  • Troop carried weapons have a range of 2 squares
  • Non-troop weapons have a range of 2 squares
A Space marine Devastator unit can choose a missile blast attack, plasma power weapon attack, or  heavy bolder support weapon attack.
Some non-troop units are able to transport troop units. Units in the transport may not be attacked.

If a transport is destroyed, then roll a D6 for each transported unit subtracting their armour value as they bail out. Placing them in adjacent squares. If there are no adjacent square, they remain with the transport in a pinned state until a vacant square is available.

Imperial Guard units disembark into cover from their Chimera transport.


Units may go into overwatch by expending a move or attack activation.

A unit in overwatch when attacked may engage the attacking unit (if within range) in simultaneous combat.

At the start of a players turn all overwatch units cease to be in overwatch, unless a player choses to place them back into overwatch via their actions.

Take Cover

A unit which is in a square with cover may use the cover value instead of their own armour value. They can must declare a unit is taking cover. 

A unit which uses cover is considered pinned (use a token to show a pinned unit).

A pinned unit's first action must be an unpinning action. Until this until a move action is used to remove the pinned in cover token. If no move (odd) activity os scored the unit remains in cover.

Where a unit is behind a square considered cover, then they too can take cover.

The Tyranid unit chose to take cover (a smoke counter is used to show they are now pinned) allowing them to use the terrain armour value of 4. The Space Marines must roll 5 or 6 to cause casualties.

Psychic Powers

A unit with psychic powers have a 2 square range. The number of D6 rolled is chosen by the attacking player up to the 4 D6. If any 1’s are rolled they are treated as a hit on the psychic unit.

Minor psychics have a range of 1 Square and major psychics a range of 2 squares.

A psychic unit choses 4 x D6 to attack a Space Marine unit who declined to take cover. The psychic unit rolls 1,3,4 and 6 resulting in 3 hits for the Marines (6 highest rolled - 3 for full armour) and 1 hit on the psychic unit for the rolled 1.

Indirect Fire

Some units are able to attack with indirect fire. They are not required to have a line of sight on the unit they are attacking, providing they can be seen by other friending units.


All attacks by and against flyers reduce a weapons range by 1 square.

Flyers can occupy any square providing it does not contain another flyer. The restriction of one unit per square does not apply if one of the units is a flyer.

Flyers can choose to move off the table and back into their army's reserve. They may return to the table in a later turn from reserves.


A player is unlikely to have all his units on the tabletop at the start of the game. One unit per turn my arrive from reserves per turn.

In most cases units will arrive on the base edge, but some units (eg scouts) can arrive on the base of side edges, and other can deep-strike and be placed anywhere on the table (eg flyers).


  1. Two Questions:

    (i) How many hits does a Troop unit take?
    (ii) A pinned unit has to use a move activation to unpin, but can it still fire when pinned?


    1. Hi. The number of models vary between 3 and 5. For example, I often have Tyranid warrior units with 3 models and 5 weaker termagant models. With space marines I go with 5 for marines and 3 for terminators. For me the available models sometimes dictate the unit's size.
      A pinned unit with two actions for example, may be unpinned and take 1 follow up action. (Thanks for the questions - I never cease to be amazed at how many assumption I make when writing rules.)

    2. Thanks. I see the bits about unit strength now.

      I'm still no quite clear on unpinning though. It's listed as a move (odd die roll) action. So if I have a pinned unit and roll two even (combat) actions does that mean it can do nothing? Or does it get the combat actions but can't move? Or does it use one of the two actions to become unpinned and then have the other?

      (if the very last one, then unpinning simply means you roll one les dice for activation, and become unpinned, since *any* result would allow it.)

      So the question - I have a pinned unit. I get 2D6 for activations. I roll two even numbers. What happens?

    3. You remain pinned, but, and there is always a but, you would essentially go into overwatch which would guarantee the unit would become unpinned next move. Not that the term overwatch works well with this situation, where you are essentially banking an activation for the next turn.

  2. Is there anywhere that I can get a copy of these sci-fi rules ?

    1. I have found a copy and can send it. If you provide an email address I will send it, then delete the comment with the email address.

    2. This comment has been removed by a blog administrator.

  3. Thanks for sharing these. I have only played them twice and enjoyed each game. I'm adapting them to my own vision of fantasy warfare too. Cheers.
    Auston Butler
    NW Arkansas

    1. Thanks Auston. I hope your adaption to fantasy style games goes well. Cheers Peter

  4. Here is a fantasy battle I fought using your rules. Had a blast.

  5. Glad you were able to successfully rework the rules to suit your fantasy games.