This is the art of Fast drawing a Melee Weapon. (Quick Draw is a similar proficiency relating to Ranged Weapons). The proficiency must be applied to a tight group of weapons.
For finesse weapons, (when the character has Weapon Finesse) this means that drawing the weapon or swapping weapons takes no time (Zero Segments).
For other weapons which have both Speed Factor 7 or less and a weight of 10 lbs or less the weapon can be drawn or swapped to with the loss of only one segment.
With a weightier or slower weapon, the time to draw or swap the weapon becomes the Weapon Speed minus 5 segments.
In contrast, a weapon being drawn and used will take double its weapon speed to attack and forgoes multiple attacks for that round.
Alfie rounds a corner, with weapons drawn and comes upon Briony who had been picking a lock. Luckily, neither are surprised but Briony is unarmed.
Their dexterity adjusted rolls are 3 for Alfie and 4 for Briony.
Alfie leaps to the attack with his longsword on segment 3. As Briony has a weapon drawn before he completes the attack, he does not get +2 to hit against an unarmed defender.
Briony spends 3 segments drawing her shortsword, (completed in segment 6), and completes her counterattack on segment 10.
If Briony had Melee Readiness in the sword she would have been able to attack and potentially kill Alfie on segment 8 (4 + 1 + 3), despite reacting after him, or 7 if she had Weapon Finesse.