2 or more fire markers made from wool shaped as thick and heavy black smoke clouds about 2 to 4 cm in diameter.
How to set fire to a place
Any Art or Bw in firing range and any unit next to a BUA, village, building, dry wood, field or grasland may try to set this on fire by attacking it normally (like foot). The attacked place defends like a Camp Follower and may use a bonus of +2 if it is wet, and another +2 if it is made from stone. If the attacker's CV is higher, the place starts to burn instantly and a fire marker is put onto it. If attackers fight defending units of a city camp or fort, they may try to set the place on fire: they tell what they want to do and fight normally. If their attack succeeds, the BUA is on fire and the defending unit must leave the place/recoil.
Effects of fire
• any units next to a fire (within 1 BW or less) fight against other units as if overlapped
• burning places can neither be entered nor crossed (HoTT: nor flown over)
• fire and smoke block LOS and distant shooting
• fire attacks all adjacent units or buildings with a standard CF of +2
• if windy, it attacks only with the wind, but with a bonus of +2
• it keeps burning until all fighting ends
• camps, Art and WWg are destroyed instantly • adjacent units of foot (not Art!) may try to prevent its spreading by fighting it normally
...about 10 years ago i made my late samurai homerules but all in german. But this is the part about fire: Set fire Ninjas or ranged troops can attempt to set fire; To do this, set fortifications or entire villages or forest areas on fire. To do this, the fire-laying element of a round must be in contact with the relevant feature, neither shooting at enemy troops nor actively engaging in close combat. If the arsonist is destroyed by enemy action or if he rebounds, his attempt to set fire is deemed to have failed. A fire-creating element requires at least a 5 (Ninjas:4) to set that feature on fire. The fire spreads directly from the source of the fire in the direction of the wind. At the end of the current round, the fire has covered an area within 3 base widths. In the following round, all troops must leave the burning area. All troops not evacuated by then are considered destroyed. From then on, the fire burns until the end of the game and is considered inaccessible to all troops. From the second round onwards, the fire covers the area within a radius of 3 base widths. In the third round, the village, temple or fortification (up to 4 base widths) burns ablaze. Smoke spreads from the source of the fire in the direction of the wind. The smoke completely blocks the line of sight. Fires cannot be started while it is raining....
...next ideas about fire are from Chris Peers rule from: too few to fight, too many to die: Arson Any fighting element may attempt to set fire to a village, tall grass, or crop if it is in direct contact with that portion of terrain during the bombardment phase. The pillaging element cannot shoot in the same round still be involved in hand-to-hand combat, and cannot complete the attempt if taken off the field. Regulars or skirmishers need a 4 or more on D6, other troops need 5 or 6 to set something on fire. A player can also try to set his own village on fire so as not to have to hand it over to the opponent. But this has a negative impact on the morale of your own troops. The entire burning village and all vegetation within 6” of the source of the fire immediately catches fire and is considered lost. By the end of the movement phase of the following round, all elements must have left the scene of the fire. Those who do not manage to escape in time are considered lost. The fire lasts until the end of the game and the entire area can no longer be entered. From the 2nd round after the fire breaks out, smoke is created which moves with the wind at a speed of 3" per round and completely blocks visibility. The wind direction when a fire breaks out is randomly determined using an agreed method