Dual Shaman is a type of map which has two shamans, blue and pink, and one or two different-colored holes. In vanilla maps, shamans only receive credits for mice entering their own hole, while in permanent user-created maps (which is labeled with two feathers), both shamans receive credits for mice entering the hole, as the holes aren't colored.
In vanilla maps (with colored holes), shamans will usually fight if one or both shamans want saves, which may result in several (or even all) innocent mice being killed during the fight, and one (or both) shaman(s) killed.
Otherwise, if both shamans are more cooperative, they will build together to both or his/her own hole and let the mice decide which hole to enter. Some might even race to be the quickest to build to their own hole.
In user-created map with one hole, the shamans should cooperate, since the map is harder to solo. Fighting is pointless since both shamans will get saves from mice entering the hole.
Spirit is a favorite technique since it can be placed anywhere on the map and is usually available. However, it will only be effective if the Shaman is near a ledge and react slowly. Keep in mind that spirit will affect you too, so you might end up just killing both your opponent and yourself, which usually can annoy everyone in the room. To spirit a Shaman off the map or into a hole, it is best to place the spark under and slightly to the side of his or her feet.
If the shaman has the anti-spirit skill, it is also possible to use that in between normal spirit to confuse the other shaman.
In a dual shaman map, a shaman can attempt to block the other Shaman's hole, or in other cases trap the other Shaman so that he is too far away to build. This forces mice to enter the blocker's hole.
This is usually achieved with red anchor planks, often with a box attached. However, blocking the opposing shaman's hole can also be accomplished with constructions using anvils, boxes, and yellow or blue nails. Certain skills can also be used to block the opponent's hole, such as Cloud or Companion Cube. Shamans should be careful they do not trap mice in the blocked off area or block both holes.
Some shaman skills can also remove a blockage. Recycling can remove red anchors and Demolition Worker can delete any summoned objects, including those summoned by skills.
With hard mode totem, it is possible to set up a totem that kill the other shaman (usually using mass cannonball). It might accidentally kill other mice or the user, though.
The cannonball, if available, is one of the more reliable ways of killing a Shaman. It is best used by tricking the Shaman into jumping, and then using the time it takes for them to fall to summon it and render them helpless to do anything against it.
One infamous technique often used on Waiting Cheese is to summon a box in front of the shaman and then shoot a cannonball in order to throw them off the map, essentially killing. If executed properly, this attack is almost impossible to avoid.
If the shaman is particularly skilled, they may shoot a cannonball your own box back at you before you can summon yours. You can avoid this by summoning a short red ghost plank between you and the box. You may also want to attach a long wooden plank rising vertically out of the box, making it impossible to jump over. This is also extremely effective when dealing with rogue mice.
Boxcar of DeathEdit
A slow but fun to watch method is to create a box around the other shaman, attach 2 balls to it, and then use runes to push it over the edge. Note that this takes very long to make and you should only do this if the shaman suspects nothing or if you have a truce. This can also be used to eliminate stallers or AFK mice. One thing to remember: Do not use a cannonball to speed up the process as a glitch may let the victim out of the car.