Imperium Chess — Storm & Ashes
STORM & ASHES 🔥
The 13th century. A storm rises on the steppe, and ten powers contend across Eurasia: the Mongol Horde, Khwarazm, the Jin Dynasty, Western Xia, the Rus' Principalities, the Medieval European Kingdoms, the Abbasid Caliphate, the Southern Song, the Mamluk Sultanate, and Kamakura Japan.
Choose your power and your enemy. Six army groups hold each realm — horse archers, heavy cavalry, infantry, shock or ranged — with four around the capital plus two vanguards on the side cities. Strike when the enemy overcommits, and flank for an automatic kill.
Take the enemy capital, or destroy their armies. Lose your own capital, and your realm falls.
- Command Medieval European Kingdoms, the Abbasids, the Mamluks, Jin (Jurchen), Song, Japan (Kamakura) — six more powers of the age.
- Challenge and invite friends to private rooms.
⚔ Objective
Two realms of the 13th-century world face off on a 7×7 board. Win by moving any of your army groups onto the enemy capital, OR by annihilating their entire host. Lose under either condition and your realm falls — until the next campaign.
♟︎ The Board & Armies
Each side has a capital at the center of the back rank (row 0 / row 6) plus two side cities on the flanks. You deploy 6 army groups: four around the capital (Left / Front / Reserve / Right) and two Vanguards stationed on the side cities. Each group is a Unit + Commander pair. You always see your own commanders; the enemy's commanders stay hidden until first contact reveals them.
🎯 Your Turn — One Action
On each turn, pick one of your living, unstunned groups and either move to a green-highlighted empty tile, or attack a red-highlighted enemy in range. Then it's the AI's turn. Horse Archers get a two-phase turn — they can move AND attack in the same action (see Unit Types below).
⭐ Army Group — Unit + Commander Synergy
Each of your 6 army groups pairs a military unit (the troops on the field) with a commander (the historical figure leading them). Both halves carry 4 stats each, and the way they combine determines how the army performs in combat.
- Military Unit stats: ATK (Attack), DEF (Defense), SPD (Speed), MOR (Morale), plus troop count. These are intrinsic to the unit type — Mongol Horse Archers are always 9 / 5 / 10 / 9 regardless of who leads them.
- Commander stats: STR (Strength), STG (Strategy), LDR (Leadership), INF (Influence). These are personal qualities of the named historical figure.
During every combat, your commander's stats compare against the OPPOSING commander's. Each point of advantage becomes a bonus on your unit:
- My STR > opp STR → +ATK (each point of difference = +1 ATK)
- My STG > opp STG → +DEF
- My INF > opp INF → +MOR
- LDR doesn't apply directly to combat math — it gates certain historical narrative triggers and special events.
Example: Mongol Horse Archers (base ATK 9) led by Genghis Khan (STR 10) attacking Khwarazmian Infantry led by Ala al-Din Muhammad (STR 6) gains +4 ATK from the STR gap — effective ATK 13. The SAME horse archers led by a lesser khan get a far smaller bonus. Same unit, very different combat performance. Choosing which commander leads which unit is half the deployment game.
A handful of named commanders are Legendary — beyond stat comparisons, they carry signature abilities that fire under specific historical conditions:
- Genghis Khan — The Great Khan: his Keshik household guard fight with +1 ATK, and any mounted unit he leads gains +1 SPD.
- Subutai & Jebe — the feigned-retreat masters: leading Mongol horse archers grants +1 SPD, turning hit-and-run into annihilation.
- Baybars (Mamluk) — The Lion of Egypt: any unit he leads gains +1 ATK and +1 SPD. Qutuz — Victor of Ain Jalut: +1 ATK against a Mongol enemy.
- Wang Jian / Meng Gong (Song) and Timur Malik (Khwarazm) — wall-holders: fortified in a friendly city they gain +1 DEF and a large troop bonus.
- Hōjō Tokimune (Japan) — Divine Wind: while he holds a friendly city, the whole realm fights with unbreakable morale.
Many other commanders carry signature abilities — Jalal al-Din, Chenheshang, Henry of Silesia, Kōno Michiari, al-Dawatdar, and more. Study them all in the Commander Codex.
♟ Unit Types — Movement & Attack Patterns
This is the heart of the game. Every unit has a distinct movement and attack range that defines its battlefield role.
- Line Infantry (Khwarazm, Jin, Song, Europe, Abbasid, Mamluk, Japan's Ashigaru) — Moves 1 tile orthogonally. Attacks 1 tile orthogonally. Backbone of every settled realm. 4,000–5,000 troops, steady morale.
- Shock Infantry & Heavy Cavalry (Samurai, Iron Pagoda Cavalry, Caliphal Guard, Mounted Knights) — Move AND attack 1 tile in ALL 8 directions. Hard-hitting elites that brawl in close quarters. The Jin Iron Pagoda Cavalry (铁浮图) are the most heavily armored troops in the game (DEF 10).
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Cavalry (Keshik, Turkic, Jurchen, Caliphal, Royal Mamluk) — Attacks ALL 8 surrounding tiles. Moves 1 tile in any of 8 directions, OR up to 2 tiles in a cardinal direction (long stride). The Mongol Keshik Cavalry (怯薛军) — Genghis Khan's household guard — is the premier shock cavalry. Cavalry has a unique charge-through mechanic: when an orthogonal enemy is at distance 1 and the cells beyond are clear, an orange ⚡ tile appears past the enemy.
- TRAMPLING CHARGE — if the cavalry wins the head-on fight cleanly, the enemy is annihilated AND the cavalry continues to the destination tile. Zero losses.
- CHARGE-THROUGH ESCAPE — if they could not win cleanly, both sides take zero losses and the cavalry simply rides past the line to reposition.
- Ranged (Song / Europe / Jin Crossbowmen, Samurai Archers) — Moves 1 tile orthogonally. Attacks any of the 8 surrounding tiles PLUS 4 cardinal tiles at distance 2 (long shot). When attacking solo, ranged units strike first, the defender cannot counter, and the ranged unit takes zero losses. After a kill they hold position. Ideal as 2v1 flank supporters — the 2-cell long shot threatens from afar.
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Horse Archers (the Mongol, Khwarazm, and Mamluk signature) — Move like cavalry (8-direction + 2-cardinal long stride). Attack with a SKIRMISHER ranged pattern.
- Stationary: shoots 4 diagonals + 4 cardinal-2 long shots (a "ring with cardinal gap" — NO point-blank N/S/E/W shots).
- After moving: shoots only the 4 DIAGONAL-1 cells. Long shots unavailable after repositioning.
- Hand Cannon (手炮 / 铜火铳 — Mongol & Song) — Moves 1 tile orthogonally and attacks like a ranged unit: any of the 8 surrounding cells PLUS the 4 cardinal tiles at distance 2 (long shot) — so it can shell an enemy two cells away, even one fortified on a city. It strikes first with no counter and takes zero losses, holding position after a kill. ATK 10 / DEF 7 / SPD 7 / MOR 8, 1,000 gunners. The 13th-century bronze hand gun the Mongols learned from the Chinese.
- Catapult / Trebuchet (投石机 / 回回炮 — Mongol, the European siege train & the Abbasid counterweight trebuchet) — Moves 1 tile cardinal. Fires into the SECOND ring only — the three cells on each side (top-3, bottom-3, left-3, right-3 = 12 cells), the four far corners excluded; CANNOT hit any of the 8 surrounding cells. It ignores DEF — kill capacity = 500 crew × 4 = 2,000 in the open field, doubled to 4,000 against an enemy packed behind city walls; annihilate-or-nothing. Useless point-blank: keep it screened and let it shatter targets from a ring away.
⚔ Combat Resolution
When you attack, both commanders reveal themselves. Stat boxes appear: ATK / DEF / SPD / MOR. Combat is fully deterministic — no dice, no randomness. The faster side strikes first; the strike compares striker's ATK vs target's DEF:
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ATK > DEF — BREACH: striker inflicts
min(striker troops, target troops)casualties. If the target is wiped or routed → destroyed; striker advances onto the empty tile (except ranged/siege attackers, who hold position, and per the City-Walls Rule below). - ATK = DEF — EQUAL CLASH: both sides take equal mutual casualties simultaneously. If both armies are wiped to zero → TRUE mutual destruction, BOTH units die.
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ATK < DEF — DEFENDED: no losses. The defender chooses to hold (stalemate) or counter-attack with full retaliation =
min(defender troops, attacker troops).
Multi-strike: when the faster side's SPD exceeds the slower's by more than 1, it gets max(1, fastSPD − slowSPD) consecutive strikes on a breach. Decisive for Mongol horse archers under Subutai or Jebe. Ranged volleys use the same math, no counter possible.
Morale rout: after taking damage, the loser may rout if (losses > 50% AND MOR-gap ≥ 2 in striker's favor) OR (losses > 80%). A routed unit is destroyed regardless of survivors.
Siege fire (Cannon & Catapult) is resolved differently — it ignores DEF, SPD and morale entirely. Kill capacity = crew × 4. If that meets or exceeds the target's troop count the target is destroyed; otherwise nothing happens. There is never a counter against a siege weapon firing over a gap.
🤝 2v1 Flanking — Auto-Win
When you attack, the engine checks whether a second friendly group is also in position to threaten the defender. If yes, the attack wins automatically regardless of stats — the defender is encircled and destroyed. Two cavalry, or two horse archers on opposite sides of a target = an inescapable trap. Ranged and horse archers make excellent supporters (their long range threatens from afar).
Realms vary widely in raw unit power — some field heavy cataphract-class cavalry, some mass crossbows, some skirmishing horse archers, some gunpowder siege. 2v1 flanking is the great equalizer. When you play patiently — thinking a turn or two ahead and arranging your pieces — the 2v1 encirclement is the surest way to bring down a strong enemy unit. No matter how powerful the defender, an encircled unit cannot survive.
🏛 City Rules
- Fortification — Standing on a friendly city: +2 DEF (capital) or +1 DEF (side city). No ATK bonus. Enemy cities give no bonus. Several commanders (Wang Jian, Meng Gong, Timur Malik, al-Dawatdar) amplify a held city into a true fortress.
- City-Walls Rule (universal) — When the defender stands on ANY city, killing them is NOT enough to take the city this turn. The attacker stays at the original tile; the city stands EMPTY. Someone must walk in on a later turn to occupy it — giving the defending side ONE chance to rush a unit into the empty walls. Storming a city always takes at least 2 actions.
🚩 Reinforcements
Capturing an enemy side city — or recapturing one of your own that the enemy has seized — summons a reinforcement army to the outer flank of that city. Most realms receive up to 2 reinforcement waves per campaign; the Mongols receive 3, reflecting the horde's bottomless reserves of riders.
Each wave brings a fresh historical figure who was NOT among your starting 5 commanders. The Mongol waves are led, in order, by Tolui (heavy cavalry), Hülegü Khan (horse archers), and Batu Khan (a fresh Keshik guard) — three of Genghis's sons and grandsons who carried the conquest from Persia to Hungary.
🌍 The Nine Realms
Mongols and Khwarazm are free to play. The other seven unlock with the Conqueror's Circle. Each realm follows a 2 + 2 + 1 shape — two pairs of supporting troops plus one signature unit — except the Mongols, who learn from everyone they conquer:
- 🏕 Mongols — the great exception. Keshik Cavalry ×1, Horse Archers ×2, Hand Cannon ×1, Catapult ×1. The only realm fielding both gunpowder and a siege engine, plus 3 reinforcement waves. Köke Möngke Tengri — the Eternal Blue Sky.
- 🕌 Khwarazm — Persianate Central Asia. Horse Archers ×1 (signature), Infantry ×2, Turkic Cavalry ×2. Jalal al-Din fought the Mongols to a standstill — under his command every Khwarazmian unit strikes with +1 ATK, the relentless raiding war of the last Shah.
- 🏯 Jin (Jurchen) — Iron Pagoda Cavalry ×1 (铁浮图, DEF 9), Infantry ×2, Jurchen Cavalry ×2. The most heavily armored host in the game.
- 🐉 Southern Song — Hand Cannon ×1 (手炮), Infantry ×2, Crossbowmen ×2. The inventors of gunpowder war; defenders who held the Yangtze for decades.
- ⛩ Kamakura Japan — Samurai ×1, Ashigaru Spearmen ×2, Samurai Archers ×2. Tokimune's realm, shielded by the kamikaze Divine Wind.
- 🛡 Medieval European Kingdoms — Mounted Knights ×1, Men-at-Arms ×2, Crossbowmen ×2. The chivalry of Poland, Hungary and the Teutonic Order. Their Couched Lance Charge hits non-ranged foes with +2 ATK — devastating in a frontal clash, but kited and nullified by horse archers, as Henry II learned at Legnica.
- ☪ Abbasid Caliphate — Caliphal Guard ×1, Infantry ×2, Caliphal Cavalry ×1, Counterweight Trebuchet ×1 (回回炮). Weak in the open field, but the Walls of Baghdad turned back the Mongols in 1238 and 1245: every Abbasid unit fortified in a friendly city gains +1 extra DEF. Only flood and treachery breached the city in 1258.
- ⚔ Mamluk Sultanate — Royal Mamluk Cavalry ×1, Horse Archers ×2, Sultanate Infantry ×2, Camel Archers ×1. The slave-soldiers who broke Mongol invincibility at Ain Jalut. Their Camel Archers skirmish like horse archers but strike only the diagonal-1 cells.
- 🏯 Western Xia (Tangut) — Iron Hawk Cavalry ×1 (铁鹞子), Tangut Infantry ×2, Divine-Arm Crossbows ×2. The Tangut kingdom the Mongols vowed to erase — armored riders and the famous 神臂弓 crossbow.
- 🔱 Rus' Principalities — Druzhina Cavalry ×1, Rus Spearmen ×2, Boyar Cavalry ×1, Rus Archers ×1. The forest-and-river princes — armored druzhina knights and stout spear-walls behind fortress cities. Alexander Nevsky holds the walls.
🎭 Historical Event Triggers
The engine fires cinematic historical popups at moments that mirror real 13th-century history — the Sack of Baghdad, the last stand at Yamen where the boy-emperor was carried into the sea, the Divine Wind that wrecked the Mongol fleet, and Ain Jalut, where the Mongols met their first defeat. Reinforcement commanders carry their own stories; the most dramatic moments often fire only after a fresh khan has landed on the field.
🔒 The Conqueror's Circle
Membership unlocks all six premium realms — Jin, Song, Japan, the Medieval European Kingdoms, the Abbasids, and the Mamluks — plus private multiplayer rooms to stage any matchup history allowed, or never did: the Song crossbow wall against Jin iron cavalry, the Mamluks against the Mongols at Ain Jalut, or clashes the distance of Eurasia never permitted. New content is added as the game grows, at no extra cost per realm.
🏆 Victory
You win the moment one of your armies steps onto the enemy capital, OR eliminates every enemy group. Lose under either condition and your realm falls — until the next campaign. One sky, one Khan.
Join the Conqueror’s Circle
Mongols and Khwarazm are free to play, no account needed.
Become a Senator to command this faction, the rebellion of Spartacus, the horse archers of Parthia, and create private rooms to challenge friends.
Currently complimentary during early access. One membership unlocks Imperium and Imperion 1776.