Polearm Weapons

Training in the Pole Arms weapon skill supports the use of polearm-based weapons such as spears, halberds, and lances in melee combat. Polearm weapons come in both one- and two-handed varieties, and the use of two-handed polearms provides a small defensive bonus to the wielder. Polearm weapons along with Two-Handed weapons tend to be the largest and heaviest-hitting weapon types. As such, they are also by and large the slowest. A reference for polearm weapon types can be found here on the Official GemStone IV website.

Characters with at least 15 ranks of the Pole Arms weapon skill can make use of the TRIP command if they have a two-handed polearm in their right hand. Effectiveness of TRIP can be increased by training in Combat Maneuvers and gaining ranks in the Trip maneuver.

Two-handed polearms cannot be used to ambush from hiding - the character will only remove themselves from hiding and attack visibly. One-handed polearms are useable for hidden ambushing purposes.

Use of the GRIP command can toggle spear- and trident-based polearms from one-handed to two-handed and back again.

Resources

http://www.play.net/gs4/info/armory/polearms.asp
http://www.play.net/gs4/info/skills.asp