For combat moves to be effective, a player must raise either Unarmed Combat or Melee Combat, preferably both.
Heavy changes to the combat system were made in the update "Bumfights".
In order to learn a combat move, an animal must be defeated in melee combat. The move learned is based on the animal defeated, but otherwise appears to be random. (Minor note: During the first iteration of combat discoveries, prerequisites to use the move had to be met. As of world 10, this is not the case and you can pick up moves at random. Some players have had issues with getting a move like chop without getting a way to gain initiative points.)
A note on "μ":
Quote from jorb:
"Spending more points on a combat effect increases the efficiency of said combat effect in that school. The meaning of increasing the weight of some particular combat effect is indicated in the descriptive text for that combat effect by a μ-symbol (Mu). The actual value of μ ranges from 1 to 1.5, depending on your weighting. Usually, a higher weight for some particular combat effect will serve to reduce its cooldown, increase its damage, or the like."
Moves in italics are available for free to hearthling when acquiring 'The Will to Power' skill.
|Move||Learned from||Initiative cost||Cooldown||Special|
||2||70/μ||Completely removes your slightest opening|
||4||45||Opportunity Knocks increases your opponent's greatest opening by 40%·μ.|
||0||30/μ||Gives +1 initiative|
||0+4||40/μ||Gives +2 initiative|
|Move||Learned from||Initiative cost||Attack Weight||Openings||Reduces||Cooldown||Special|
||35||For every unit of opening reduced by Feigned Dodge, twice that amount is given to the opponent.|
|Watch Its Moves||
||45||Gains you 1 point of initiative against your opponent.|
|Move||Learned from||Block weight||Cooldown||Special|
||Melee·250%·μ||25||If Shield Up is used without a shield equipped, its block weight will be 50% instead of 150%.|
|Move||Learned from||Initiative cost||Attack weight||Attack type||Openings||Damage||Grievous damage||Cooldown||Special|
||According to weapon||10%||50|
||According to Weapon·150%||80|
||According to weapon||40|
|Go for the Jugular||
|Knock Its Teeth Out||
||10||30%||50||Gains you 1 point of initiative against your opponent.|
|Punch 'em Both||
||10||7.5%||40||Attacks both your primary target and also one other opponent in range.|
||According to weapon·110%||55|
||According to weapon·75%||25|
||None||40||To the extent that it is unblocked, Steal Thunder will take 3 points of initiative from its target and you will gain 2 of them.|
||According to weapon·125%||50||Any pointed weapon.|
|Storm of Swords||
||According to weapon||70||Storm of Swords will attack up to five opponents in range, starting with your main target. The targets will receive 100%, 125%, 150%, 175%, and 200%, respectively, of the weapon's damage.|