Two Weapon Combat

Training in Two Weapon Combat (TWC or 2WC) allows a character to swing a weapon in his or her off-hand.

Ranks and Training Point Costs

Type	Square			Semi			Pure
Profession	Rogue	Warrior	Monk	Bard	Paladin	Ranger	Cleric	Empath	Savant	Sorcerer	Wizard
Max Ranks Per Level	2	2	2	2	2	2	1	1	-	1	1
Training Point Cost	2/2	2/2	2/2	3/2	3/3	3/2	9/9	12/12	-	12/12	12/12

Pros and Cons

The biggest benefit of two weapon combat is the extra swing that the character gets. There are a few things that are different when a weapon is swung in the off-hand, such as roundtime, attack strength (AS), and defensive strength (DS).

Roundtime

Roundtime is calculated based on the base roundtime of each weapon, the weight of the off-hand weapon, and the user's strength. Swinging two weapons at once is far faster than swinging each of the weapons individually, but only fast off-hand weapons add no penalty whatsoever to swing speed. For the lowest roundtime, the weapon in the off hand should be at least as fast as the weapon in the right hand and should not be very heavy. To use an off-hand weapon without penalty, you must have the following strength bonuses:

Off-hand Weight	Minimum Strength Bonus
3 pounds	+5
4 pounds	+20
5 pounds	+35

See the Melee Roundtime article for an in-depth discussion of the factors that go into the calculation.

Attack Strength

The AS of a swing takes into account the character's skill with the weapon itself, and their skill in TWC. 3/5ths of one's skill in the weapon type accounts for the character's AS, while 2/5ths are the character's training in TWC itself. Also, if a character's strength bonus is higher than the character's dexterity bonus, the off-hand attack will be limited by the character's dexterity. More often than not, this comes into play when a character uses the combat maneuver, Surge of Strength.

Additionally, a character that trains in TWC twice per level has no chance of "not finding an opening for the off-hand strike" when swinging at a target up to five levels higher than themselves. Less training reduces the chances of the off-hand strike from occurring. Training in TWC 1.5 times per level reduces the level of the guaranteed strike to like-level with the swinger, and training only once per level reduces the chances to 80% when swinging at a target that is the same level as the swinger.

Defensive Strength

A character's DS when using an off-hand weapon is calculated similarly to the DS granted from their primary weapon training. While the primary weapon grants DS according to the following formula

Parry DS = (Weapon ranks+(STR/4)+(DEX/4)) × (0.20 + stance/2) + (stance × 50)

Off-hand weapon DS is calculated by the following formula:

Off-hand Parry DS = (TWC ranks+(STR/4)+(DEX/4)) × (0.10 + stance/4) + (5 or 15)

Where stance is 0.00 (in OFF), 0.20 (ADV), 0.40 (FOR), 0.60 (NEU), 0.80 (GUA), 1.00 (DEF), and STR and DEX refers to the bonuses given to the Strength stat and Dexterity stat. The +5 at the end of the formula is +15 instead if the user is wielding either a main gauche or a sai in the off-hand.

A character's DS with an open off hand is calculated slightly differently:

[(TWC Ranks + trunc(STR/4) + trunc(DEX/4) + enchant bonus/2) * Stance modifier] + (5 or 15, depending on training)

Stance modifiers for empty off hand are 0.10 (in OFF), 0.15 (ADV), 0.20 (FOR), 0.25 (NEU), 0.30 (GUA), 0.35 (DEF). The +5/+15 at the end of the formula depends on your TWC training; a character with at least 0.5x TWC per level receives the +15 modifier.

Weapons and TWC

Weapons that require two hands to wield, such as the claidhmore and lance, generally cannot even be swung with a weapon in the off-hand, let alone used in two-weapon combat. Almost all one-handed weapons can be used in the off-hand, but there are a few notable exceptions. The so-called "bastard" weapons that can be wielded one- or two-handed via the GRIP have various limitations or outright restrictions in two weapon combat.

Weapon	Effect/Limitation
main gauche	Provides +10 DS when wielded in the off hand
sai	Provides +10 DS when wielded in the off hand
whip-blade	Cannot be used in TWC for lore reasons
pilum	Cannot be used in TWC
spear	Cannot be used in TWC, even when GRIPped one-handed.
bastard sword	Can be used only in the main hand, and only when GRIPped one-handed.
katana1	Can be used only in the main hand, and only when GRIPped one-handed. Katanas receive -10 AS when a weapon (or any other item) is held in the off-hand.

¹A few katanas in game were created before the actual katana weapon was coded. These "old-style" katanas were falchions (and possibly other weapon types) altered to be called a katana, and thus follow the rules of that weapon base

Resources

• http://www.play.net/gs4/info/skills.asp#twoweaponcombat
• http://www.play.net/gs4/info/combatguide.asp#factors
• Two Weapons Combat Officials folder
• Nilandia's guide on archive.org