Dojo Darelir, the School of Xenograg the Sorcerer

Tag: tactics

Terrain Appreciation

August 2, 2025

[Colonel Glover] Johns was a “basics” man and a total soldier. He taught—and insisted that his company commanders teach—things like terrain appreciation, the knowledge of which was a basic tool of a soldier’s trade: to be able to look at a piece of ground and appreciate the slightest differences in the contour; to notice how the ground unfolds and be able to think There’s cover over there—cover, the one essential, providing protection from direct enemy fire; to recognize a stream line, a gully, or a treed area as an avenue of approach through which a unit could move unseen; to understand and identify the best ground from which to launch or repel an attack. Shoot, scoot, and communicate—the “three R’s” of infantry….

About Face, Chapter 12

Author’s emphasis.

One Weapon Fighting Against Two

November 4, 2024

After a brief ritual salutation, Marangan’s student came at me. He was using two sticks, wielding them in a series of complex patterns that made it difficult to judge potential angles of attack. I engaged my opponent cautiously, then backed out of range again and again as I assessed his skills.

Most times in the Japanese arts, you’re going up against a single weapon. They have a preference in Japan for the commitment this engenders. But, of course, it also tends to create a flaw in your training. After all, the old samurai carried a long and a short sword. What if an opponent used them both?

There are varieties of double-handed weapon systems in the Japanese arts. Miyamoto Musashi was famous for his nito style, using long and short blades simultaneously. And you occasionally run up against people in a kendo dojo who use it today. As a matter of fact, Yamashita would sometimes insist that I watch these people and train with them. Not to adopt their style—”the road to perfection is steep enough carrying one weapon, I think, Professor”—but to learn how to combat it.

And what had I learned? Basically that if you’ve got one weapon and the other person has two, you’re in for a rough ride. And the only way to beat them is to use an attack that is so precise, well timed, and focused that it cuts through the cloud of uncertainty that the opponent has created. And that’s not even it. You have to feel the opponent’s pattern in your gut and then when it happens—if it happens—your response snaps out like an electric spark, almost independent of your control.

You just have to hope you don’t get pounded to death while you’re waiting for the spark.

Tengu, Chapter 15

Eternal Rules For a Cavalry Charge

October 23, 2024

The cavalry action was a technique of warfare seldom practised any more, except on some feudal or xenos worlds. It was a throwback to an antique age of conflict, when military superiority was weighed on a different scale.

But the technique had not disappeared entirely. It had evolved, and disguised its true nature under a veneer of modern technology.

That was what this was, the raw truth of it. A cavalry action. A charge. The simple rules had been laid down long ago, before man reached out to the stars.

The first: maintain formation. Start steady, and do not race ahead of your fellow riders.

The White Scars ran out of the ground smoke in a wide, blade-edge fan. A perfect formation. They came from the south-eastern end of the Colossi outworks, sweeping around north in an arc like the swing of an axe. Three hundred and thirty jetbikes, gunning together. The roar of them was like a scream. Slow smoke tumbled in their backwash, accelerated, whipped, tortured into streamers and whirls and even halos, as the White Scars punched through thicker banks. Crimson pennants bent and cracked from the red-and-white vehicles: Bullock-pattern, Scimitar-pattern, Shamshir-pattern, Hornet-pattern, Taiga-pattern.

Burr stared.

The second: put your spur to your steed only when the enemy is in range.

The formation, already moving, as it seemed to Burr, with dazzling speed, somehow accelerated. The agony-howl of the massed engines intensified. The enemy line, shield wall and extended storm-force had broken step and slowed. They had seen what was coming. Weapons drew up. The jolting gun-wagons began to turn, or stopped to traverse their pintle-mounts. Maintaining the arc line, the formation bore down on them, unfaltering, unyielding, low-level, a racing blur, like a pack of target-locked missiles. The stained light glinted off the blades of the ordu: lances, drawn tulwars, glaives. At the heart of the line rode the Khagan, the Khorchin Khan of Khans, astride his monstrous voidbike. His sabre rose.

Time slowed down, as time always seems to do when something terrible is about to happen. The enemy columns started shooting frantically. The Great Khan’s sabre swung down.

The White Scars began to fire.

Bike-mounted bolters, heavy bolters, some in pairs; rotary guns housed in the nostrils or chins of their snarling steeds; plasma and lascannons; volkite culverins. A raking hurricane of destruction. Contrails and streamers of grey and black weapons-exhaust dragged out behind the bikes like banners. The discharge of it was heart-stopping, the continuation of it numbing. The roar, a frenzied drumming of heavy bolters, sounded, to Burr, like the thunder of hooves, the stables of a god unslipped at full gallop.

There was no ranging fire. The White Scars already had their targets. The first gun-wagons exploded. Others lurched, hammered, buckling. Fireballs lit off across the extended enemy mass from east to west. The storm troop lines began to fracture. Some broke. Some ran. Some tried to retreat towards the sally gaps in the shield line. Whole echelons were mown down where they stood, bodies twisting and lifting, and disintegrating in clouds of churned earth and stitching impacts. A few, unscathed, tried to fire back.

Rule three: shock is the action’s best weapon.

The White Scars ripped in, never for a second breaking formation, despite the gunfire that clipped at them and tore at their armour. One jetbike cartwheeled, gushing flame, rider lost. No one looked back. The bikes crossed the line of the already-dead, the blackened bodies littering the ground, and their anti-gravitic down-force bent, tossed and flipped the slain as they rushed over, their kills jerking and dancing.

Impact. The first ordu riders reached the standing lines. Their guns were still reaping the enemy formations down. They punched through the breaking ranks, crushing through upright men, running over them, smashing them into the sky. Broken forms were thrown up and back, spinning slack and disjointed. Others burst against speeding armoured prows, washing the white ground-smoke red with puffs of aerosolised gore. Lances impaled, glaives scythed. Swords flashed, hooked, slashed. Burr saw one White Scar streak across an overturned gun-wagon. A traitor on its flank aimed a volkite pistol. The White Scar’s back-extended tulwar met his fist before he could fire, splitting the pistol end to end, the hand at the thumb, and the entire extended arm lengthways to the shoulder, where the blade-tip dissected the man’s head too. A kill from the saddle. All in one forward rush. The jetbike was past and on, even as the man spun and fell, sliced through, the cell of his pistol detonating like a flash grenade.

They reached the shield line, slaughter in their wakes. At close range, the bike guns fractured and crumpled the thick sheets of storm-plate, but they could not break them. They broke formation instead, rushing in through the wall gaps or over the shield line, entirely.

Then they fell upon the vast host sheltering behind.

The fourth rule: if you break the enemy line, you are in the heart of them, and war becomes the melee of hand to hand.

From Emplacement 12, Burr could no longer see the White Scars. The shield wall and the smoke screened off the havoc that followed. It was, perhaps, a blessing he was spared the sight. It becomes hard to trust as brothers, those you have seen capable of unbridled savagery.

For the White Scars, the rapacious V Legion, the far side of the wall was another world. Speed, shock and rate of fire had swept them to the shield line with devastating effect. But crossing the wall line had robbed them of speed and line discipline, and the odds were reversed. They were inside the choking enemy mass. Each rider, in a second, had passed from the bright smoke of the open field into a vast back-line of standing infantry. The rain seemed heavier, a curtain unfogged by the blanket of smoke. The assault host was immense: thousands of storm pikes, dripping with rain, ranked for assault; hundreds of thousands of traitor infantry; ready lines of armour, engines revving; monstrous formations of the Death Guard.

The Death Guard. Of all the Traitor Legions, the Death Guard was the one most despised by the White Scars ordu, and the feeling was mutual. The war between the XIV and the V had become a blood feud that would never be cooled. Hatred was too small a word. Even on this precipice of history, the White Scars were known as wild hunters, carefree killers, warriors who laughed in the heat of action, delighting in the fire of war.

There was no laughter now.

Nor were the Great Khan and his warriors fazed. They had done this before. Indeed, they had all known, from the moment they committed to the charge, that this was the goal. Unless enemy fire brought them down in the charging line, this was the highest purpose of a charge action: to reach the enemy, to meet his main strength, to engage, to be in his midst. They knew what to do. Physical momentum had been lost, but a momentum of mind took over.

They broke into individual actions, maintaining as much speed as they were able, preserving what collective forward movement they could. They thrust through the waiting ranks, or dropped into them. The bikes themselves were weapons: their armoured prows, their mass and motion, the crushing downward force of their repeller systems. The traitor host, far larger than even the Great Khan had been expecting to find, was war-ready, but it was not prepared. They were drawn up in deep, pre-battle cohorts. Their sight lines generally blocked by the shield wall, they had no idea what was coming at them. Only the roar of guns and the scream of engines had suggested that anything was.

The White Scars riders slammed down into them. Many came nose up, rearing, allowing their lift-systems to hammer the first rows off their feet. Their guns cycled, chewing into the bountiful, waiting lines of targets. Some shots passed through two or three lines of bodies. This was greedy killing. They were spoiled for targets, because they were vastly unnumbered, surrounded on all sides by armed, but as-yet undeployed enemy combatants. There was a kill to be made in every direction.

The enemy mass collectively flinched from the points of attack, the host rippling like a pool of oil as it recoiled. Men fell against, and into, other men as they scrambled away from the killers entering their positions.

But the White Scars were truly outnumbered. Traitors mobbed them from all sides, blasting weapons point-blank, heedless of their own kin, striking and battering with whatever blades and mauls were in their hands. Riders and bikes became mired in scrums of attackers, fighting from the saddle in the driving rain, lopping off every hand and head and pole-blade that came at them. Thickets of pikes speared two of them from their steeds, punctured in a dozen places. Gunfire destroyed the engine of a running jetbike, and its rider leapt clear, allowing the burning, tumbling machine to power into the enemy files, killing a score with its shredding mass, and then another score with its detonation. But the rider, Kherta Kal, was on foot, alone, encircled and rushed.

The Death Guard surged forwards, fighting through their own dazed foot troops to meet the White Scars. They were driven by transhuman reaction, sheer outrage at the audacity of the assault, and, more than anything, hatred. The desire to close with and punish their arch-foes, who had been fools enough to ride in among them. The brute horror of the Death Guard was plainly visible, a spasm of sadness to the heart of every rider. They beheld their once-brothers, pitifully transformed: massive armoured thugs, their grey-green plate greased with rain, streaked with rust and seeping fluid, rank and diseased, their armour swollen as though expanded by infected bloat within, jet and ebon-iron visors formed like howling beasts and wild-wood predators.

Legionary met legionary, dots of gleaming white engulfed by tides of mottled verdigris. Tulwars and sabres slashed down from saddle height, splitting dark plate like rotten squash and pumpkin, spraying ginger and yellow gouts of pestilential matter. Filthy spears, black as charcoal, plunged into burnished white ceramite, squirting scarlet into the rain, unseating riders, carrying them down under weight of numbers, some White Scars taking eight or ten fatal blows before they hit the mud.

The ground beneath was a deep mire, a liquid black morass, thrashed up by the shield tractors and the advancing host. It spattered and clung to the boots and legs of the churning Death Guard, and splashed the flanks of the wallowing jetbikes.

Wild chaos. The deepest and most intense melee. No rules, no order. A frenzy. An overwhelming din of blows and impacts, bolter blasts, shrieking engines. A tulwar splitting a houndskull helm and the skull inside. A dirt-crusted warhammer breaking chestplate, bone and muscle, pulverising heart and organs. A White Scar lifting clean from the saddle, impaled on a dark serrated lance. A Death Guard squad leader mangling against the snout of a surging bike, knocked down, shredding in the repulsor field. Flying flakes of armour. A spinning visor, torn off. Dismembered limbs, spinning aside, some still clutching weapons or parts of weapons. Gore splashing up to meet the hellish rain.

In the heart of it, the Great Khan. Almost unassailable in his might, but the greatest focus of the traitor wrath. He had dared to come among them, to enter their heart. He had wounded them savagely, broken the day’s assault, but it would cost him. His was the trophy-head they most desired, the unthinkable kill they suddenly craved. A chance, an opportunity no traitor heart had dared imagine.

They swarmed.

But to take their prize, they had to kill him, and Jaghatai Khan was not in the mood to meet death. The vast and feral melee in the traitor back-lines was not a dismal misadventure to end a glorious cavalry action. It was just the far-point of the rush, the true price demanded of the enemy when the charge began.

Rule five: if you have driven through the enemy mass, turn and charge them again from the rear.

The Khan swung his dao, cutting through armour like fat. The war-calls of Chogoris bellowed from his lips, drowned out by the impossible deluge of the battle.

Yet they were heard.

Jetbikes gunned. Engines rose at the sound of other engines shrieking. Bikes turned, ramming through bodies, swinging sideways to fell others with deliberate and brutal sideswipes of the flanks and rear ends.

The White Scars broke back. One by one at first, following the Khan’s lead, then en masse, breaking free, accelerating, retracing their rush back to the wall. They turned high to break out, but then swept low again, prow-rams, chattering gun mounts and raking blades slaughtering any who had survived their outward run, or any who had been foolish enough to try and surge in at their backs.

Almost as many traitors fell to the rear-charge as had died during the in-rush.

The White Scars raced towards the rear of the shield wall. Kharash riders split sideways as they approached the shields, running the length of it, tossing saddle charges into the unprotected backs of the massive field tractors.

None had been set with more than a cursory fuse. The mines began to detonate, some only seconds after the Kharash rider had sped past. Tractor mounts blew up, shearing apart in searing clouds of flame, bodywork splaying, stanchions fracturing, frames collapsing, engines bursting, splintered axles spinning clear from each inferno.

Shield sections fell. They remained, true to their construction, for the most part intact. But, torn from their supporting frames, they toppled forward flat into the mud, a wall no longer.

Eight tractors died. The advancing rampart was broken, like a broad smile with teeth missing, black smoke swilling from the gaps. The White Scars burned through the heavy smoke, taking full advantage of the clear passage provided by the annihilated sections. Some Kharash paused as they turned out of their breaking action, halting to haul fallen or wounded brothers up onto the bikes beside them. Yetto of the Kharash found Kherta Kal still alive, drenched in gore, standing alone with enemy dead heaped around him. He pulled him onto the flank of his steed, and bore him out of hell.

Burr saw the first riders punch out of the seething smoke. He started to cry out, a whoop of joy and shock, but it died in his throat. There could only be a few of them. The glory of the charge had gone into the darkest pit of the enemy. Precious little could return from that.

But more appeared. Then more still. Not all, but a startling number. Dozens. Hundreds. Their return ride, harried by parting shots from a wounded enemy mass, had little of the original discipline in its formation, but formal discipline no longer mattered. Some riders were wounded. Others, running more slowly, carried wounded men with them, clinging to the sides, or even held limp across the hulls in front of the saddles.

“I’m dreaming, surely,” Burr murmured. He looked at Raldoron. “How could any of them have survived? Not just any, but so many?”

“Are you awake, Konas?” Raldoron asked. He had removed his helm, and was staring out at the ruined enemy line and the returning riders. There was no expression on his face.

“I am, lord,” said Burr. “I’m sure I am.”

“Then know, you have seen the White Scars do what the White Scars do,” said Raldoron. “It is rare for any to witness it. I confess, I have relished it every time I’ve been lucky enough to watch it happen.”

“It’s not…” Burr began. “This isn’t a game! A…display!”

“No,” Raldoron agreed. “It never is. And certainly not here, in this time of darkness. What you just saw, Konas, was fortune favouring us for the day. But you should still enjoy it for what it was. Great art must be appreciated, no matter the situation.”

The first riders were approaching the outworks.

The entire cavalry action had lasted six minutes.

Saturnine, Chapter 4

Emphases mine.

Guile

November 30, 2023
[Commander Riker is allowed only 40 crew on an obsolete starship for a combat simulation, but 40 of his choosing. He goes to the quarters of Worf, the Klingon member of the Enterprise‘s crew.]
Commander Riker:
You know of the simulation. What do you think?
Lieutenant Worf:
Waste of time.
Commander Riker:
It’s just designed to be an exercise.
Lieutenant Worf:
Useless. If there is nothing to lose—no sacrifice—then there is nothing to gain.
Commander Riker:
You mean besides pride. Well, in this case, it doesn’t matter. I probably haven’t got a chance.
Lieutenant Worf:
[defensive] There is always a chance.
Commander Riker:
Slim. The Hathaway‘s most sophisticated weapons system, even in a computer generated mock-up, can’t hope to defeat the Enterprise.
Lieutenant Worf:
Well, still—
Commander Riker:
You’re outmanned, you’re outgunned, you’re outequipped. What else have you got?
Lieutenant Worf:
[ponders for a moment before looking up in challenge]
Guile.
Commander Riker:
[smiles]
Join me.

— “Peak Performance” – Star Trek: The Next Generation, Season 2 (1989)

No Rules In Mortal Combat

April 29, 2022

They would fight not only without quarter but also without rules. In mortal combat, unlike a friendly tournament, nothing prevented a man from stabbing his opponent in the back or through the eye-slits of his helmet, or blinding him with sand, or tripping him, or kicking him, or jumping on him if he should slip and fall. In a duel fought in Flanders in 1127 the two exhausted combatants finally threw down their weapons and fell to wrestling on the ground and punching each other with their iron gauntlets, until one reached under the other’s armor and tore away his testicles, killing him on the spot. Chivalry might have been alive and well in jousts of sport, and even in the preliminary ceremonies of the judicial duel, but once the actual combat began, chivalry was dead.

The Last Duel, Chapter 9

Use Your Weakness

January 12, 2022
Max Suba:
Make yourself aware of your own weaknesses, as well as those of your opponents. The good ones try to cover theirs up. The great ones use theirs. Use your weakness.

— “By The Sword” (1991)

Guerrilla Warfare Is as Old as Mankind

October 16, 2021

Guerrilla warfare is as old as mankind. Conventional warfare is, by contrast, a relatively recent invention…. The first genuine armies—commanded by a strict hierarchy, composed of trained soldiers, disciplined with threats of punishment, divided into different specialties (spearmen, bowmen, charioteers, engineers), deployed in formations, supported by a logistics service—arose after 3100 [B.C.E.] in Egypt and Mesopotamia….

Considering that Homo sapiens has been roaming the earth for at least [150,000] years and his hominid ancestors for millions of years before that, the era of conventional conflict is the blink of an eye in historical terms….

Throughout most of our species’ long and bloody slog, both before the development of urban civilization and since, warfare has been carried out primarily by bands of loosely organized, ill-disciplined, lightly armed volunteers who disdain open battle. They prefer to employ stealth, surprise, and rapid movement to harass, ambush, massacre, and terrorize their enemies while trying to minimize their own casualties through rapid retreat when confronted by equal or stronger forces. These are the primary features both of modern guerrilla warfare and of primitive, prestate warfare whose origins are lost in the mists of prehistoric time…. Guerrillas therefore may be said to engage in the world’s second-oldest profession, behind only hunting, which draws on the same skill set.

Invisible Armies, pp. 9-10

How about hobgoblins and orcs fighting like this?

Supernatural Tactics of the Mongols

November 16, 2010

The Mongols even resorted to supernatural means to assure their success. They asked Tenggri, or Heaven, for his favor on the battlefield, in the same way that Muslim and Christian armies appealed to their god. But the Mongols also employed other supernatural tactics, of which the most important was weather magic, conducted by a shaman known as the jadaci.

Several accounts mention the use of weather magic. The jadaci used special rocks known as rain stones, thought to be imbued with the power to control weather, in order to summon rainstorms, or even snowstorms in the summer, which caught the enemy ill-prepared. The Mongols, who had lured their opponents away from their base, took shelter during the storm and then attacked while their foes were disoriented. A prime example of this tactic was recorded during the war against the Jin after Chinggis Khan’s death. Bar Hebraeus relates that Ögödei resorted to using rain stones after he saw the size of a Jin field army. After he had lured the Jin away from any support, he called upon his jadaci to summon a storm. The ensuing downpour, in the normally dry month of July, lasted for three day and three nights. The Jin army was caught in the open and drenched while the Mongols donned rain gear and waited the storm out. They then turned around and ambushed the Jin army, annihilating it.

Other sources indicate that Tolui, rather than Ögödei, was the general involved in this episode. Tolui had retreated after encountering a much larger Jin force, and after the Jin had attacked his rearguard he summoned a Turkic rainmaker to perform his magic. Rashid al-Din recorded that ‘this is a kind of sorcery carried out with various stones, the property of which is that when they are taken out, placed in water, and washed, cold, snow, rain and blizzards at once appear even though it’s the middle of summer.’ The rain continued for three days, changing on the final day to snow accompanied by an icy wind. The Jin troops were exposed to this severe weather while the Mongols found shelter. After four days of snow, the Mongols attacked and destroyed the bewildered and weakened Jin troops.

The Mongol Art of War, pp. 81-82

This is the first explicit reference I have found of the use of magic in warfare.

Covering a Withdrawal

May 1, 2008

To ensure that his brigade and its battalion rearguard were neither enveloped nor routed in withdrawing, [Prussian General] Steinmetz dispatched a fresh infantry and cavalry regiment ahead to Gosselies, thereby observing the sound principle that in rearguard actions the withdrawal of engaged units should be covered by troops already in position.

Waterloo: New Perspectives, p. 159

Archer-Pair in Assyrian and Persian Warfare

March 7, 2003

The Assyrians had made major and highly effective use of a tactical feature common in Near Eastern warfare for many centuries. This was the archer-pair, consisting of a spearman bearing a very large, light but sturdy shield made of leather and wicker, and an archer; the spearman faced the enemy and held up the shield, behind which the archer hid and fired off volleys of arrows. The Persians called such shields spara and so named these tactical units sparabara, or “shield-bearers.” Typically, the Assyrians had lined these units up side by side, forming a single row of shield carriers backed by a single row of archers. [The Persians] increased the depth of the formation and also the number of archers per shield, producing a heavier concentration of arrow shot.

The Persian Empire, pp. 27-28

Javelins versus Chariots

March 7, 2003

Toward the end of the second millennium [B.C.E.], however, this humble weapon seems to have enjoyed a brief prominence. For the ‘hunting’ of chariot horses the javelin must have been ideal: although it would seldom have killed the horse that it hit, the javelin would surely have brought it to a stop, thus immobilizing the other horse, the vehicle, and the crew. Composite bows were appropriate for the chariot warrior, but for a runner a far preferable long-range weapon would have been the javelin. Javelins are thrown on the run, whereas an infantry bowman would have to shoot from either a crouching position or a flat-footed stance (in either case offering chariot archers a stationary target). In addition, the javelineer could carry a small shield, whereas the archer had to use both hands to work his bow. That javelins were in fact used against chariots in the Late Bronze Age is clear from Ramesses the Great’s account of his valor at Kadesh: in the ‘poetic’ inscription Ramesses boasts that the Hittites were unable either to shoot their bows or to hurl their javelins at him as he charged against them in his chariot.

The End of the Bronze Age, pp. 181-82

Deception in War

March 7, 2003

The most potent weapon in any soldier’s arsenal is deception. That you don’t hear much about deception in warfare tells you something about how elusive and apparently rare this item is. Yet, as the ancient Chinese adage puts it, “There can never be enough deception in war.” Sun-tzu went further, saying, “All warfare is based on deception.”

Victory and Deceit, p. 1

Battle of Leuctra

February 6, 2002

Thebian phalanxes in echelon at Leuctra

The Spartans drew up for battle in the conventional phalangial line, the best troops on the right, a few cavalrymen and light troops covering the flanks. They expected the Thebans to form in similar fashion. In such a battle the Spartans, superior both in numbers and in fighting quality, would unquestionably have been victorious. Epaminondas, however, refused to fight on Spartan terms. He quadrupled the depth of his left wing, forming a column 48 men deep and 32 wide. The remainder of his army, covered by a cavalry screen, was echeloned to his right rear in thin lines facing the left and center of the Spartan army. This is the first known example in history of the deep column of attack and of a refused flank, prototype of the holding attack and main effort of more modern times. Epaminondas personally led his left-wing column in a vigorous charge against the Spartan right, while his cavalry and the infantry of the refused center and left advanced slowly, occupying the attention of the Spartans to their front, but without engaging them. The Spartans were hopelessly confused by these novel tactics. The weight of the Theban column soon crushed the Spartan right. Epaminondas completed the victory by wheeling against the exposed flank of the remaining Spartans, who promptly fled when simultaneously engaged by the Theban center and right. The Spartans lost over 2,000 men; Theban casualties were negligible. Spartan military prestige was shattered forever.

The Encyclopedia of Military History, pp. 42-43

Tactical Capabilities of Medieval Weapon Systems

November 7, 1997

With heavy infantry specialized to resist heavy cavalry and light infantry indispensable in sieges and finding its most effective employment in the field against light cavalry, the art of war about the year 1200 [C.E.] had these clearly distinguishable capabilities (using the symbol → to mean was superior to):

heavy infantry → heavy cavalry
heavy cavalry → light infantry
light infantry → light cavalry
light cavalry → both heavy infantry and heavy cavalry.

tactical schematic in two dimensions: infantry vs. cavalry, heavy vs. light

These relationships are conveniently summarized in schematic [above], in which A means ability to attack successfully in the direction of the arrow and D means ability to defend successfully in the direction of the arrow. Attack includes the capability to compel the attacked to fight; defend implies only the capacity for successful resistance but no ability to force action. The schematic assumes a flat surface.

The ability of the cavalry to dismount modifies this diagram. When the heavy cavalry dismounted it became heavy infantry, and confirmed the generalizations that the man on foot is superior to the mounted man and [that] the defensive is stronger when the same weapon systems confront one another. Light cavalry could gain comparable advantages by dismounting, and in each case the dismounted cavalry in the defense could easily take advantage of terrain or artificial obstacles, something more difficult to do mounted. Medieval soldiers grasped and often exploited the value of dismounting heavy cavalry but, lacking light cavalry, could never make use of this transformation. They did occasionally mount bowmen, giving them the strategic mobility of the light cavalry. They more rarely resorted to a similar mounting of heavy infantry, probably because of their ample supply of heavy cavalry. Yet to have mounted heavy infantry on nags would have been a far more economical solution had knights customarily fought on foot. It would have saved the considerable cost of a robust war horse and the expensive, but unused, skill in fighting mounted.

The Art of War in the Western World, p. 145-46