One-Hour Wargames Marengo - Part 2: Terrain and Movement

Side note: despite having finalized these rules months ago - and routinely playing them – my progress on such things as diagrams and ‘proper’ draft writing occurs at a glacier’s pace. I always find more satisfying to actually play a wargame rather than writing about it; I’m afraid I’m not much of a blogger. Anyway, I’ll keep putting my finalized designs here for future reference.

In the previous post, I have broadly outlined the size of both the playing map and the playing pieces of my OHW Marengo scenario. It’s time to find how to make those blocks move around the battlefield in a way which makes (at least some) historical sense!

Starting from the map (again)

The first thing I did was to survey the square section of the historical map I decided to use for my OHW scenario and take notes about which types of terrain I needed to model the overall course of the battle:

Map 1: OHW-style square battlefield.

As I mentioned in the previous post, some of the features are a bit puzzling, so I’ve referred to a later map (approximately from the 1870s) to understand e.g. what exactly happens to the southern portion of the Fontanone. Unfortunately, this wasn’t very successful as the landscape seemed to change quite a lot during those 70-ish years, with the Fontanone being replaced by two different streams called Rio Boggio and Rio Ressia… In fact, I suspect that “Fontanone” (big fountain/canal) might just be a funny name for any small water course in the local dialect, just as “montagnone” (big mountain) might ironically denote any ditch higher than 10m. At least, the later map was useful in making me understand that all those straight lines in the SW corner of the map aren’t most probably roads, but irrigation ditches.

Map 2: Istituto Geografico Militare Survey Map (apparently from the 1870’s?)

It became immediately apparent that I needed a lot more terrain types w.r.t. OHW’s RAW. Based on the previous two maps, I’ve outlined these terrain types on the map itself:

Map 3 – Terrain types:

Blue – Watercourses (thick: major, thin: minor)
Dark Green – Woods
Light Green – Marsh/Muddy
Yellow – Ploughed Fields
Yellow with Green outline – “Alberata e Seminativo” fields (more on that below)
Red – Conurbations & smaller Built-Up-Areas, e.g. walled farms
Contour lines (uncolored) – Hills
Dots (uncolored) – Orchards
Most remaining lines – Road network (paved, dirt, or tree-lined avenues)

Just looking at the annotated map makes some aspects of the battle much clearer. For example, Marengo was just one of the many BUAs in the area, but it had the only solid bridge in the whole area across an almost uninterrupted series of creeks and marshes. Austrian artillery and cavalry just needed to clear that chokepoint – no wonder it became the crux of the battle. If you just treat anything east of the Bormida as clear terrain (as some rulesets do) then the historical Austrian course of action make no sense at all. In fact, Austrian troops emerging from the bridgehead just had four broad choiches:

(1) press forward along the road through Pietrabuona and Marengo: obvious choice but one with several drawbacks (COA historically followed by e.g. Kaim’s and Morzin’s troops)
(2) take the road to Castelceriolo: potentially decisive but very slow (COA historically followed by Ott, Schellenberg, Vogelsang etc)
(3) try to cross the Fontanone near La Barbotta (attempted e.g. by Elsnitz and Frimont)
(4) try to follow the eastern bank of the Bormida then cross the Fontanone at the ford (no ‘solid’ bridge there!) near La Stortigliona (disastrously attempted by O’Reilly)

…anything else seems highly unlikely. This means that all the advantage in cavalry and artillery by the Austrians is severely hampered by the terrain and that the French can concentrate their defense on a few well-chosen chokepoints. Moreover, the mere size of the Austrian army implies that they cannot choose the same COA for all troops: there’s just no space to do that. They need to split their force across the four possible approaches.

So far so good! But I needed to actually translate all of the above into OHW rules. This is what I’ve done:

Amendments to movement rules

First of all, I didn’t change OHW’s RAW movement rates, because they don’t seem too different to what everyone else is doing in other rulesets. Movement rates are quite tricky because they’re unavoidably intertwined with the modeled timescale: how far a formed infantry battalion can march in a turn depends on how much time a turn represents, of course. Moreover, even if I rigidly defined the length of a turn, I could only compute movement distances for formations moving in straight lines for the whole time – thus not taking into account formation changes, pauses, bursts of hyperactivity in response to enemy actions, etc etc.

OHW movement rates just imply that cavalry can on average move twice as fast as formed infantry, and I’m content with that for two reasons. First, it’s one of the parameters that Mr. Thomas took into account when fine-tuning OHW’s scenarios, so messing with that would impair the compatibility of my amendments with the scenarios as written – something I’d like to avoid. Second, I’ll be able to retroactively make movement rates as ‘realistic’ as possible by varying turn length and finding which one produces the most historical results. For this reason, I’ll leave the exact duration of one turn undefined for the moment. All in all, the movement allowances I’m using are the following:

Formation	Movement allowance per turn
Line Infantry	6” (250 m)
Skirmishing infantry	9” (375 m)
Heavy Cavalry	12” (500 m)
Artillery Battery (limbered)	6” (250 m)
Artillery Battery (unlimbered)	0” (0 m)

 …and here are some of the revised shooting ranges for comparison, but I’ll talk about those in a future installment (spoiler alert!):

Shooting Unit	Effective range
Musketry	3” (125 m)
Artillery (direct)	24” (1000 m)
Artillery (bounce)	36” (1500 m)

 While movement rates are more or less the same as in the Rules-As-Written (RAW), I use the following amendments to how movement is actually performed:

Interpenetration

Line infantry and cavalry can pass through artillery if they face the same direction as artillery AND artillery doesn't move this turn. Skirmishers can pass and be passed through anyone, at any angle (as per the RAW).

Columns of route (road movement bonus)

Road movement bonus is 6” (instead of 3” as in the RAW) for all units. However, to qualify for the bonus units must spend their entire move (including the extra 6”) on the road network, and they must pivot in a specific way at the end of the move, simulating the adoption of a non-combat formation: they must end their move with both of their flanks touching the road (see Figure 1), i.e. as if moving ‘sideways’ so to speak. Of course, only one unit can occupy a given length of road at the same time. Following this rule, units in column of route can get a substantial movement bonus but will arrive at their destination in a suboptimal combat formation (since they’ll need one further turn to attack anything in the general direction of their movement, or to avoid flank charges/enfilade extra hits).

Figure 1 – Columns of route and road movement. Left: The cavalry unit (below) has a normal movement allowance of 12”, so it can just move this far without restrictions (orchards and ‘normal’ fields are clear terrain, see below). The three infantry regiments only move 6”, but they decide to use the extra +6” road movement bonus to keep up with cavalry. To qualify for road movement bonus they must end their move with both flanks on the road; if they do so, their centre point can move 12”. Right: position after moving. The cavalry squadrons could move 12” without pivoting and are ready to charge any enemy appearing on their West; the three infantry regiments are instead in column of route, stretched out to around 750m along the road and not in a position to immediately project maximum offensive or defensive potential to the west.

Cavalry charges

Cavalry must have LOS to their target at the start of their move. Due to this, charges cannot be performed e.g. when interpenetrating an intervening friendly unit, or towards unseen enemies beyond a ridge. Cavalry can still charge when negotiating a bottleneck and/or when receiving a road movement bonus; in this case however they end their charge ‘sideways’, with their short flanks contacting the opponent (again, simulating suboptimal combat formations). Such hasty/constrained attacks only inflict 50% hits on the target.

Figure 2 – Cavalry charges. Left: both Futak 1° and Futak 4° dragoons are 18” away (I always measure distances via front centre points) from enemy formed infantry. Right: Futak 4° decides to use their standard 12” movement allowance to get closer to Chambarlhac’s men with all squadrons in line. Instead, Futak 1° are on a road and decide to stretch out into a hasty charge adding a +6” bonus to their 12” move. They can charge Chambarlhac 24°, but squadrons reach the enemy lines in a more piecemeal fashion: under my amendments, this is abstractly represented by putting the block ‘sideways’. This hasted charge will inflict half the usual amount of hits.

Rivers, Creeks and Streams

Major rivers such as the Bormida are impassable and can only be traversed at a ford or fixed/pontoon bridge (see below). Lesser but relevant water courses  such as the Fontanone creek can be crossed by infantry (both line and light) at any position, but crossing is hindered (i.e. must happen ‘sideways’, see below). Lesser water courses are impassable to artillery and cavalry; but while cavalry can still cross these at fords, artillery needs ‘real’ solid bridges such the one at the Marengo fortified farm. Infantry units (both line and light flavours) can cross lesser water courses at any point. Infantry units in contact with rivers of all types receive cover from attacks coming from the opposite bank (both shooting and charges – provided the latter are possible of course).

Bridges, fords, pontoons, bottlenecks and traffic jams

All units can only move across major bridges as part of a road move (see Figure 3a). Units crossing at fords and pontoon/minor bridges must in addition end their moves with their central point *on* the bridge/ford (Figure 3b - in practice, only one unit will be able to cross per turn). If the crossing point is not connected to a road then the crossing unit must also end with both its flanks on a line perpendicular to the edge of the just-negotiated obstacle (Figure 3c).

Figure 3 – Crossing at fords, bridges, etc. (a) Major bridge crossing. The Bormida is impassable along its whole course to all troops; the tête-de-pont at Alessandria is across a major bridge. All units must cross the bridge by normal road movement (see Fig. 1 above). (b) Road movement with no bridge. Elsnitz 3° Dragoons start their move on a road, so they could gallop up to 12+6=18” if they remained in column of route. However, they reach a ford much sooner. They must thus stop with their centre point on the ford, still in column. (c) Creek crossing with no road or bridge. Minor streams/creeks can be traversed at any point along their course by infantry, but units must stop with their centre point on the obstacle and forming column of route ‘as if’ on a perpendicular road.

Major conurbations (“Towns”) and smaller Built-Up-Areas (BUAs)

All unit types can occupy (i.e. end their move inside) towns; but only infantry can occupy BUAs. Units in towns and BUAs count all their sides as “front”; they can thus shoot 360° and cannot be charged/shot “in the flank/rear”. In addition to this, line and light infantry only receive 50% hits when attacked. Artillery cannot fire while in a town. Cavalry can only charge units inside towns and BUAs as if it was using road movement (regardless of whether they’re actually on a road or not at the start of their move); that is, they must charge “sideways” (inflicting 50% hits, see above).

Marshes / muddy ground

Artillery cannot enter these at all, and their cannonballs won’t “bounce” (details in the next instalment). Cavalry can move through it by suffering a weak (1d6-2) attack each turn due to the resulting chaos.

Alberata e Seminativo

Old‑fashioned vineyards as very, very probably in use near Marengo at that time (see also this excellent post). My late father used to work for the Italian ministry of agriculture, and I remember him telling me how modern/mechanized techniques really changed the way people used to grow vines. I remember how he explicitly talked about ‘alberata e seminativo’ (which is a modern agronomy name for an ancient practice) as an example. In old times (but in some remote places or in small family farms, probably up to the first half of XX century), vines were not usually assigned their own piece of turf, but were grown on fruit trees planted in straight rows around ploughed fields. Irrigation ditches were dug between adjoining fields. In a way, you can think of ‘alberata e seminativo’ vineyards as a (less extreme) version of bocage.

So my proposal for representing them at Marengo is to make them impassable to both artillery and cavalry. I know this sounds harsh, but I think it really makes sense when considering the historical course of the battle, and specifically the very limited impact all those Austrian cavalrymen made even after negotiating the main chokepoints.

Woods and hills

As per the RAW.

Ploughed fields and orchards

I’m inclined to treat these as clear terrain for no particular reason other than the battlefield seems already quite constrained as it is now. I’ll change this later if needed…

Design Notes

The only ‘exotic’ mechanism introduced in these amendment is the funky ‘sideways’ movement used to represent non-combat formations. I didn’t want to introduce any new marker/status/etc in addition to the hit track already used by OHW, and I think this works in a very abstract way. Basically, both columns of route and disordered/constrained formations are represented by turning the unit sideways with respect to the direction traveled. It’s a bit difficult to get tournament-tight wording on this, but I hope the schemes above convey the basic idea. I think it’s also a very simple way to model road traffic jams and units stretching out when in road column. Combined with the new artillery rules (see next post!) and cavalry charges, this also models the vulnerability of these formations to shot, as well their less-than-ideal combat efficacy, for almost no extra rules overhead.

Some of the various terrain-related amendments will probably have marginal impact at Marengo, but I feel they make sense. For example, defending/attacking towns and chateaux with dragoons and the like becomes possible, although far from ideal; this might perhaps come into play around Castelceriolo.

On the other hand, I feel some of the terrain amendments are crucial to really bring the Marengo map to life for OHW play. The most prominent example of this is probably that now ‘real’ bridges become more important than temporary/non-obvious crossing points (making that Marengo bridge all-important) and that creeks can be important defensive features (thus making defending the Fontanone a viable strategy).

In the next post, I’ll detail the combat-related amendments. In the meanwhile, take all of the above strictly just as my 2 pennies – pardon, Marengos…