| The NES manual introduces Genghis Khan as "the latest in a trilogy of historical simulations" from Koei. | p. 1, Introduction | Manual |
| Genghis Khan has two scenarios. Mongol Conquest starts in winter 1174, with the goal of uniting the 14 Mongol tribes; World Conquest starts in winter 1205, with the goal of unifying 27 Eurasian countries. | p. 5, Scenarios | Manual |
| Uniting the 14 tribes advances Mongol Conquest to World Conquest, where Temujin becomes Genghis Khan. | p. 5, Scenarios | Manual |
| World Conquest offers four rulers, Genghis Khan of the Mongol Empire, Richard I of England, Alexius III of the Byzantine Empire, and Minamoto no Yoritomo of Japan. | p. 5, Scenarios | Manual |
| Mongol Conquest is for one player, and World Conquest is for up to four, who take turns as different rulers. | p. 9, Number of Players | Manual |
| A year has four turns, one per season; each turn the player gives three orders in the base country and one in each directly controlled country. | pp. 5–6, How to Play | Manual |
| The computer issues the orders in a prince-controlled country, following the policy the player sends; a directly controlled country takes one order per turn and cannot issue War or Move. | p. 6, Types of Countries | Manual |
| The NES main display lists 14 commands, Tax, Assign, Give, Train, Trade, People, View, Move, Policy, Treaty, Spy, War, Pass, and Other. | pp. 13–14, Main Display Commands table | Manual |
| Every command needs minimum levels of the lord's abilities, and a lord who lacks them cannot carry it out. | p. 13, Main Display Commands | Manual |
| Lords and princes have six abilities, Leadership, Judgment, Planning, Charm, Body, and Battle, each with a maximum of 999. | p. 8, Abilities | Manual |
| Abilities fall each time the lord carries out an order, and the Train command raises them. | p. 8, Abilities | Manual |
| A lord or prince who wins a war gains Leadership 30, Judgment 15, Planning 10, Charm 10, Body 20, and Battle 25; a lost war changes nothing. | p. 20, Command <War> | Manual |
| The drafted population works in five groups, townspeople, masons, food producers, artisans, and soldiers; townspeople set the economy, masons the defenses, food producers the fall food tax, and artisans the specialty items. | p. 14, Command <Assign>p. 12, Country Datapp. 12–13, Country Data | Manual |
| The tax rate can be set from 1 to 100, and changing it affects morale. | p. 14, Command <Tax> | Manual |
| Severe cold waves strike northern countries in winter, major storms strike southern countries in summer, and epidemics strike any country at random in spring and fall. | pp. 22–23, Natural Disasters | Manual |
| A peasant uprising occurs when the tax rate is high or morale is low. | p. 23, Rebellions | Manual |
| The draft can mobilize at most 50% of the people not yet drafted, and drafting lowers arms, skill, and morale. | p. 15, Command <Train>, Peoplep. 17, Command <People>, Draft | Manual |
| Each spring the peasants receive food equal to half the population, everyone ages a year, children may be born, gold taxes come in, and each soldier is paid 1 gold; a food shortfall shrinks the population and a gold shortfall shrinks the army. | p. 22, Game Events, Springp. 22, Game Events, Spring | Manual |
| Each fall, food and specialty items come in as taxes, in amounts that depend on the number of laborers in each group. | p. 22, Game Events, Fall | Manual |
| Every person ages one year each spring, and anyone who reaches the end of his life span dies. | p. 22, Game Events, Spring | Manual |
| The NES manual says children are born at random each spring, less often as the lord ages, and that a lord can have at most five children. | p. 22, Game Events, Springp. 7, Children | Manual |
| Princes are generals chosen for loyalty and skill as well as the lord's sons, and a lord can have at most five. | p. 7, Princes | Manual |
| A son 10 years or older can be promoted to prince. | p. 17, Command <People>, Promote | Manual |
| A daughter 8 years or older can marry a prince, who then carries the family flag; princes with the family flag never rebel. | p. 17, Command <People>, Marryp. 7, Children | Manual |
| If the lord dies in World Conquest, a son 10 years or older can succeed him; without one, the game ends. | p. 7, Lords | Manual |
| Three merchants trade in Genghis Khan, Chinese, Islamic, and Uighur, each working independently along its own sales routes. | p. 15, Command <Trade> | Manual |
| When a merchant is in the country, the player can sell food and specialty items for gold, buy food, specialty items, and weapons, or hire mercenaries, at the current market rate; weapons raise the arms value and cannot be resold. | p. 16, Command <Trade>p. 16, Command <Trade> | Manual |
| The main display shows the current market rate. | p. 10, Main Display, item 7 | Manual |
| Mercenaries are hired at the current market rate; they add soldiers but lower morale, arms, and skill. | p. 16, Command <Trade>, Hire | Manual |
| The merchants deal in 17 goods, from fur and silk to pikes and bombs. | p. 21, Merchant's List | Manual |
| Weapons bought from merchants raise the arms value, which falls every winter and whenever new recruits join. | p. 13, Country Data, Arms | Manual |
| The Treaty command asks a country to become a vassal, to pay tribute, or to ally, and success depends on both countries' conditions and the lords' abilities. | p. 19, Command <Treaty> | Manual |
| An alliance lasts five years, during which neither ally may attack the other. | p. 19, Command <Treaty>, Ally | Manual |
| Spying costs gold, 10 to scout a country, 50 to wreck an enemy's town and castle, and 100 to attack a lord, which halves his abilities if it succeeds. | p. 20, Command <Spy>p. 20, Command <Spy>p. 20, Command <Spy> | Manual |
| Going to war costs gold equal to the number of soldiers taken, plus food for them. | p. 20, Command <War> | Manual |
| In battle the attacker gives orders to all of his units, then the defender to all of his, and one day ends. | p. 27, Combat | Manual |
| A battle may last 30 days for each order the attacker had left when he declared war, up to 90 days. | p. 27, Combat | Manual |
| Moving onto a battlefield square costs 3 mobility on plains, 4 in forest or a town, 5 in mountains or a castle, 6 in desert, and 8 on oceans and lakes; forest, mountains, desert, and water also cost soldiers on the march. | p. 25, Topographical Map | Manual |
| Cavalry start a battle with 10 mobility and infantry and archers with 8; only infantry can ambush, and only archers can fire on an enemy one square away. | p. 26, Unit Type | Manual |
| A unit that passes gains 1 mobility, up to 15 for cavalry and 13 for infantry and archers. | p. 31, Battlefield Command <Pass> | Manual |
| An army wins when the enemy's command unit is destroyed, its commander flees, surrenders, or is captured in a duel, or it runs out of food; an attacker who reaches his last day loses, and if both armies die together the defender keeps the country. | p. 27, Conditions for Victoryp. 27, Conditions for Victory | Manual |
| A commander may challenge the enemy to one duel per battle; a refusal lowers the enemy's abilities, and a win that fails to capture him brings 20% of his soldiers over. | p. 30, Battlefield Command <Attack>, Duel | Manual |
| The Famicom manual lists 15 commands, with Ordo seventh; the NES manual lists 14 and has no Ordo. | pp. 13–14, Main Display Commands table | Manual |
| The lord can lead a war himself or send a prince in his place. | p. 20, Command <War> | Manual |