Bolt Action: Assault Tactics

A discussion and maybe some maths on when to assault in Bolt Action v2.  Infantry assault is a zero sum gambit in Bolt Action.  With some exceptions such as the Japanese who keep rolling until they are all gone an infantry assault involves both sides rolling to kill and the unit with the most losses being removed.  In v1 there was a bonus to assault as the assaulting unit shed all its pins.  Tough fighter has now been reduced from rolling double dice to rolling dice that hit as additional attacks.  Both of these changes have reduced the overall appeal of assualt.  The short answer should be don’t; unless your unit acts like the Japanese or key ground has to be taken to win or contest the game.

The maths behind assualt is important but the situation where it all goes belly up has to be considered.  In a recent game a British flamethrower team had run up to within 6″ of a German squad.  The Germans had already activated and the flamethrowers having a big order dice advantage in the dice bag were hoping to pick first dice next turn.  Jerry got the first dice, assaulted in (target within 6″, no defensive fire), scored zero hits, the flamethrower scored 1.  This was so unexpected that I let the German redo the action (having suggested it as a no brainer in the first place) as a fire order, close range, small team, down (5s to hit), hit for a pin but no damage.

Here are the key rules to consider for assault.  As well as line of sight, 1 figure must be within 12″ of the target in the open.  The whole unit can then move in (page 76 last paragraph) but will take defensive fire if the target has no order dice.  This will be at 12″ or maximum range of any defending weapons (page 76 3rd paragraph). Some attackers could end up moving more than 12″(page 79 1st paragraph).  If the target has an ambush dice then shooting will be at point blank range.  In the case of a target wholly in cover the charge range will be 6″.  A target at the very edge of cover will be assaulted at 12″ (page 57 ‘shooting from cover’).  The other crucial effect of cover or a defended obstacle is that both sides roll to hit simultaniously, an attack in the open has the defender take assault losses before they roll.  The 6″ and 12″ ranges are so important that they are best checked with a measuring stick rather than waving a tape measure about.

The latest errata is some help on the subject of going through cover:   ‘Note also that, if the target unit is more than 6″ away, and the assaulting unit could move up to 12″ and reach its target by going around rough ground or an obstacle, the assault is allowed (though the defensive positions bonus still applies as the defenders have time
to see the enemy running around the rough ground or obstacle)’.

The simplest scenario is an assault in the open but taking defensive fire.  The attacker is hoping to have sufficient figures left after defensive fire to hit enough defenders to render any remaining defensive rolls insignificant.  For regulars vs regulars in the open hits will be on 3’s with subsequent kills on 4’s that is a 1/3 loss ratio based on the defender’s numbers coming in.  The surviving attackers will kill regulars on 4’s then take any defensive assault losses.  So take the attacker’s initial strength and reduce by 1/3 of the defenders to work out the hits. To cut the amount of data to a reasonable level units of 1-10 men are used in these examples.  A LMG and its loader is 2 men in assault but 4 shots on incoming fire so would skew the numbers again.

AttackerHits = (attacker-(defender/3))/2

DefenderHits = (defender-AttackerHits)/2

This data shows that with equal numbers it is equal losses even considering the attacker rolling first

Attacker Hits Defender Hits
1 0.33 1 0.33
2 0.67 2 0.67
3 1 3 1
4 1.33 4 1.33
5 1.67 5 1.67
6 2 6 2
7 2.33 7 2.33
8 2.67 8 2.67
9 3 9 3
10 3.33 10 3.33

If the defender were on ambush they would be hitting on 2s (5/6), killing on subsequent 4s (5/12 combined) so there are less attackers and more defenders left to fight back:

AttackerHits = (attacker-(defender*5/12))/2

Attacker Hits Defender Hits
1 0.29 1 0.35
2 0.58 2 0.71
3 0.88 3 1.06
4 1.17 4 1.42
5 1.46 5 1.77
6 1.75 6 2.13
7 2.04 7 2.48
8 2.33 8 2.83
9 2.63 9 3.19
10 2.92 10 3.54

In the case of an assault into rough ground both sides will assault at the same time.  The attacker will take the same losses on the way in but defender hits (if regular) will be half their starting number.  No need for a separate table for that.  It is most likely that an assault into cover will start within 6″ so no defensive fire and both sides rolling at the same time based on their starting strength.

When assaulting inexperienced troops in the open they are + 1 on shooting to hit (4 to hit, still 4s to kill; 1/4 kill ratio) and are killed on 3s.  With regulars coming in at over 6″ and no ambush

AttackerHits = (attacker-((defender/4))2/3)

DefenderHits = (defender-AttackerHits)/2

Attacker Hits Defender Hits
1 0.83 1 0.08
2 1.66 2 0.17
3 2.5 3 0.25
4 3.33 4 0.33
5 4.17 5 0.42
6 5 6 0.5
7 5.83 7 0.58
8 6.67 8 0.67
9 7.5 9 0.75
10 8.33 10 0.83

Assualting veterans is risky as they need 5s to kill:

AttackerHits = (attacker-(defender/3))/3

DefenderHits = (defender-AttackerHits)/2

Attacker Hits Defender Hits
1 0.22 1 0.39
2 0.44 2 0.78
3 0.67 3 1.17
4 0.89 4 1.56
5 1.11 5 1.94
6 1.33 6 2.33
7 1.56 7 2.72
8 1.78 8 3.11
9 2 9 3.5
10 2.22 10 3.89

So what can be gathered beyond the fact that the author likes maths?  A Spread-sheet helps but these figures are not hard to work out in your head during a game.  Assault is a big risk and needs something to skew the odds.  Having the defender pinned to reduce incoming defensive fire is good.  Having them spend their dice on something other than ambush before you come in is better.  Don’t let inexperienced troops anywhere near an assault on either side unless the game depends on it.  Relying on some fraction of a whole to win an assault is not going to work out.  If the numbers predict a 2:1 kill ratio it is worth considering going in but do think of the consequences if it all goes wrong.  Having said that Bolt Action is only a game and it is more fun to ‘go for it’ and take risks than to sit back and hope for a draw.