Further interpretations of interpenetration

[Erpingham]

In response to Chris Hahn's article in Slingshot 329, I have begun a topic in which further consideration can take place.

[Imperial Dave]

so, do we have a viewpoint on this from 2 perspectives - as readers of history and as wargamers? Are the 2 mutually inclusive?

[Andreas Johansson]

so, do we have a viewpoint on this from 2 perspectives - as readers of history and as wargamers? Are the 2 mutually inclusive?

Sorry for sounding like a broken record, but we again need to consider scale and abstraction.

In the real world, all interpenetration boils down to passing through gaps - no individual soldier ever passes through another. It may be gaps between individual files or between larger unites like centuries or squadrons, but gaps of one kind or another.

For a wargame the question then is, do we represent the relevant gaps directly on the tabletop, or do we abstract them away as included inside our figures, units, or elements?  Gaps between individual files are only going to be directly represented in 1-1 skirmish games, but gaps between squadrons or the like may go either way in a battle scale set.

Interpenetration rules are only called for when we've abstracted away the relevant gaps. If they're directly represented we just move our toy soldiers through them.

[RichT]

What Andreas said.

I was glad to see I was part of the triumvirate by the way. A great honour. Also a veteran, which I suppose is good.

From reading Chris' literature review of rules, it seems there are three approaches:

- only light infantry and light cavalry can interpenetrate, and they can interpenetrate any
- others (all?) can interpenetrate, but (apart from LI and LC) they suffer a penalty eg disorder
- everybody can interpenetrate everybody else

To use Dave's categories, as a reader of history I'm pretty sure that:
- light infantry could interpenetrate heavy infantry (by passing through the diastemata kata taxeis, whatever precisely that means)
- light infantry and most cavalry could probably interpenetrate other cavalry (because cavalry squadrons formed up with gaps between them acc. to Polybius)
- cavalry could probably interpenetrate heavy infantry (judging by Arrian and Byzantine examples)
- (following from above) drilled infantry could probably open gaps to allow cavalry or anyone else through, or indeed enemies (chariots, Gaugamela, elephants, Zama)
- Roman legions could interpenetrate other Roman legions (again precise details of how obscure, but they could do it)

As a wargamer - I don't need to care about all this as I play high level gridded games where all this can be abstracted away. If I did play traditional games, I would probably either want to enforce something like the above, or keep it simple; actual examples of all the above are very rare except LI through HI and Leg through Leg - so I would allow those and ban the rest.

[Imperial Dave]

I guess, we can become too distracted by the thought process of interpenetration on the battlefield rather than the actual recorded examples or implied abilities of troops. So generally do we accept that drilled troops (regulars if you like) are much more likely to be able to allow interpenetration than say warbands or tribal bodies - of course the order is important. We could take this discussion beyond the confines of the mechanics to the examination of the actual circumstances - eg if bodies tended to approach in open order then this shouldnt present too many issues as opposing lines close, so formations close up making this process much more difficult. Is the best advice to stick to abstract means but apply grades of interpenetration depending on the proximity to battle the bodies are?

[Andreas Johansson]

From reading Chris' literature review of rules, it seems there are three approaches:

- only light infantry and light cavalry can interpenetrate, and they can interpenetrate any
- others (all?) can interpenetrate, but (apart from LI and LC) they suffer a penalty eg disorder
- everybody can interpenetrate everybody else

One needn't go very obscure to find other approaches. Frex, DBMM allows mounted to interpenetrate foot (with some exceptions, because Phil Barker). I believe I've seen similar things in other sets, but can't think of an example right now.

So generally do we accept that drilled troops (regulars if you like) are much more likely to be able to allow interpenetration than say warbands or tribal bodies - of course the order is important.

As Jim mentioned in the original thread, at the "Elephant Battle" the Galatians are supposed to have opened their ranks to let their chariots pass through.  Now, does this mean that irregulars could also manage the trick, or that the Galatians were more regular than we tend to give them credit for - or that Lucian, writing centuries after the event, got it wrong?

[Justin Swanton]

Not only Republican Roman but also armies of the Italian peninsula commonly employed two infantry lines (the Romans later refining it into 6 before finally settling back to 3) - Livy: 2.19; 2.65; 9.32; Dionysius: 8.85.1.  Regardless of the scale, it make sense to physically represent these lines on the wargaming table, particularly as the second line could sometimes be used independently of the first, for example to counter the envelopment of a wing - Dionysius: 9.11.3. Since one line would take over from the other that means the front line fell back through the rear line. So for Romans, Latins, Sabines, Samnites, Volscans and others we need to allow interpenetration of heavy foot through heavy foot.

[Imperial Dave]

I am inclined to at least countenance the ability of quite a few troops to allow interpenetration as long as they were not in close proximity to massed bodies of charging enemy. 

[Erpingham]

Nice to see things already in swing

I agree there are two sides to this - the quest for evidence of what happened and the best way of representing it on a wargames table.

Given that our actual evidence is less full than we would like, we need to think how much we abstract things, based on scale and granularity, as already said.

For example, there are plenty of examples of early medieval cavalry withdrawing behind close-order infantry to regroup but fewer details of what happened.  It seems likely that gaps were left/opened to let them fall back.  We don't actually need to know if we abstract, but how we envisage it may help us build a comprehensive whole.  For a start, early medieval infantry weren't drilled, so we need to allow this as a possibility to undrilled troops.  It appears that this role was understood as part of a plan.  Should it need some kind of command involvement to make it happen (whatever your complex manoeuvre test is perhaps)?  What happens if one or other party is disordered?  If we think of it as cavalry funneling through gaps, we have the analogy of pursuit to a castle or town gate, where attackers may be able to infiltrate with fleeing friends.  How do we play that?  Following the analogy, if the troops were sufficiently under control, their commanders could refuse to allow the cavalry through but the cavalry could try to force the issue.

Another area I'm not sure that has been fully explored is exchanging troops within a unit.  The Byzantines, for example, could move rear ranks through to the front of their formations.  Swiss pike blocks could extract halberdiers from the middle of pike blocks and detach them to act semi-independently on the flanks.  How widespread was this?  I'm assuming that we don't need a mechanism, just a rule that says "Byzantine infantry in good order can exchange ranks" or the like.  Or we abstract another stage and just assume that they follow their exchange drill at the appropriate time and give them combat bonuses in the circumstances in which they do this (in this case, an anti-cavalry bonus).

[Imperial Dave]

yes, how do we model it on the tabletop. I am very uncertain myself as to the best mechanism. I have half a mind to model skirmisher screens as part of 'normal' massed line bodies that disappear once the first clash occurs and assume that they interpenetrate and 'disappear' at this point. Other troops just cover with rulings even if it 'looks' odd that close formed infantry pass through others and vice versa

[Anton]

This is shaping up nicely.

On Dave's last point does anyone know of a case where skirmishers couldn't interpenetrate their own main body and consequently were massacred?

[RichT]

On Dave's last point does anyone know of a case where skirmishers couldn't interpenetrate their own main body and consequently were massacred?

All that springs to mind is Zama - not necessarily skirmishers, but a case of a main body not allowing friends to pass through, with bad results for said friends.

Generalising from this - passing through should normally be allowed (Hannibal had to specifically prevent it) but with possibility of bad consequences (which is why Hannibal prevented it).

[Justin Swanton]

On Dave's last point does anyone know of a case where skirmishers couldn't interpenetrate their own main body and consequently were massacred?

All that springs to mind is Zama - not necessarily skirmishers, but a case of a main body not allowing friends to pass through, with bad results for said friends.

Generalising from this - passing through should normally be allowed (Hannibal had to specifically prevent it) but with possibility of bad consequences (which is why Hannibal prevented it).

Interesting as one can possibly infer a couple of things from this passage:

1. Defeated troops expected to fall back through the support line behind them - that's what the support line was there for - so normally speaking Hannibal's veterans should have let them through, which implies they should have been in open order to facilitate the smooth passage of the Gauls and Carthaginian levies through their  files.

2. The veterans were not actually a support line but there for a different purpose, and hence were not disposed to received troops through their files. They may well have been originally intended to envelope the Roman foot a la Cannae and were disguised to look like a support line, but did not have time to switch to open order and become one as the troops in front of them fell back.

[Imperial Dave]

good points Justin. I maintain that experienced bodies of troops would be familiar with maneuvers to allow forward screens or other troops at predetermined points of the battle of signals as long as there was sufficient time to do so. Maybe Zama is the exception that proves the rule?

[Nick Harbud]

Not sure if this has any place in the current discussion, but as well as voluntary interpenetrations, one can also consider cases of involuntary interpenetration or bursting through. 

In the Battle of Culloden, the redcoats were deployed in three lines as shown below.  Each line had 3 ranks of close order infantry, but there was the distraction of musket volleys and bayonets to consider.  In their time-honoured fashion, the highlanders charged furiously.  Quite a lot of them made it through the first line, significant numbers made it through the second line and there was at least one mad individual who fought his way through the third line, after which he apparently succumbed to his injuries.

Hope this helps.