Infantry Supporting Fire Exposed

When a French attack column crashes into a defended line on the wargaming table, few mechanics trigger more heated debates than supporting fire from adjacent friendly units. While 18th-century military doctrine explicitly built defensive formations around mutual support, historical evidence and period mechanics show that static infantry could only deliver a tiny fraction of their full firepower to aid a neighbor.

Period tactical manuals, clearly demonstrate that no unit was ever meant to fight in isolation. Defensive arrays relied heavily on interlocking fields of fire. For instance, hollow infantry squares deployed in a checkerboard pattern (échiquier) spaced 100 to 120 paces apart created lethal crossfires against charging cavalry, a layout that proved crucial along the Mont-Saint-Jean ridge at Waterloo. Similarly, line infantry relied on enfilade fire (tir d'enfilade) to catch attacking column flanks in a funnel of crossfire, a tactic Arthur Wellesley famously deployed at the Battle of Talavera in 1809.

Despite the foundational doctrine of secours mutuel, static infantry in a shoulder-to-shoulder line faced extreme physical constraints that prevented them from bringing anywhere near full firepower onto a target charging an adjacent unit. Standing two or three ranks deep with men spaced just 21 to 24 inches apart, soldiers could physically swing their musket barrels only 15 to 20 degrees to either side without endangering the comrade next to them. Consequently, an adjacent static regiment could bring only 10 to 20 percent of its total musketry to bear, as only the few platoons on the immediate inside flank held a clear line of sight. Furthermore, as the charging column closed within 50 yards of the target unit, the firing angle for neighboring static troops became so acute that continuing to shoot risked hitting their own allies in the side, dropping static supporting effectiveness to zero at the moment of impact.

To deliver significant supporting fire, adjacent infantry had to physically maneuver by wheeling their end companies inward to form a concave bracket or L-shaped trap. This maneuver could raise firepower effectiveness to 30 to 50 percent or higher, but it required strict drill discipline under dense black powder smoke and left the wheeling unit's outer flank completely exposed to secondary attacks.

Artillery operated under entirely different physical rules. Guns were spaced six to ten yards apart to allow crew movement and pivoted on a single axle. A gun crew could easily traverse a cannon carriage 30 to 40 degrees in seconds without altering the unit's overall formation alignment. This mobility allowed adjacent batteries to routinely deliver 60 to 100 percent of their full firepower across a neighbor's front. At ranges over 300 yards, batteries poured solid roundshot down the flanks of advancing columns. As the target closed within 300 yards, gunners loaded devastating canister shot, switching to double-canister under 50 yards to sweep away entire ranks in a single blast.

Commercial wargame designers heavily reflect these historical realities across popular rulesets. Systems such as General d'Armée, Field of Glory: Napoleonic, and Bataille Empire penalize static adjacent infantry fire by roughly 50 percent through arc and dice-pool modifiers, while keeping flank artillery canister fire at full lethality. Black Powder caps all closing fire to a single die per unit, limiting supporting infantry to roughly 33 percent effectiveness. Empire V and VI restrict fire strictly to the physical figures falling inside a narrow 45-degree cone, while Lasalle abstracts the process entirely by forcing players to spend command momentum on Interrupt actions rather than granting free charge support.

When our umpire umpire steped in, it was to correct a mistake of his own making in his home brew rules. His mid game correction capped defensive fire of static neighboring infantry during a charge, and history it seems, was firmly on his side. Period commanders actively relied on mutual support, but allowing static infantry to pour full firepower into an adjacent combat ignores the geometric realities of linear musketry. To achieve high-potency supporting fire on the battlefield, a commander either had to maneuver their companies into an angled position ahead of time or anchor the line with a dedicated battery of artillery loaded with canister.