The King of Fighters 2002 UM/Defense

Guard Cancel CD (aka Blowback Attack aka Guard Attack etc.)

Press C + D while in blockstun. It cancels the blockstun by a blow that knocks down the opponent. The Guard Cancel CD has short frames of invincibility at startup, but has a recovery. It can get you out of a lot of attack strings while you block, and resume the pace of the match. It does little damage when it hits (it is possible to kill an opponent if it removes the remaining life to them). However, its use is limited by 3 factors:

1. It will cost you one level of your super meter
2. Your opponent might try to bait your Guard Cancel CD by making you whiff a standing CD while you're in blockstun, which has a slow startup and exposes you to heavy punishment. If you sense that bait attempt, just try to block instead.
3. This move is not instantaneous and it does have startup. You cannot punish EVERY attack with a Guard Cancel CD successfully, and you can be exposed to punishment at the end of it.

Guard Cancel AB (Break Roll/Guard Roll/Guard Cancel Roll)

By pressing only A + B or back + A + B back (to Guard Cancel Roll backwards), while in blockstun, it is possible to roll forward or backward. This roll is completely invincible and unthrowable, and has no frame of recovery. This is one of the most important defensive elements to learn and master, but also one of most outstanding features of the defensive system in KOF.

1. It will cost you one level of your super meter
2. If performed at the wrong time and inaccurately, a punishable and fully throw vulnerable regular, normal roll may happen instead or a crouching A (See also Details of the system: priority buttons).

Quick Recovery (Recovery Roll/Fall-breaker/Tech-Roll/Quick Rise)

When hit by a move that'd lead to a soft knockdown, if you press A + B just before touching the ground, you will perform a 'recovery roll' or 'quick recovery'. It's a sped-up animation of a normal roll that's fully invincible and unthrowable from start to finish. For the pros of recovering faster, giving your opponent less oki or even punishing them for using a move with too much recovery, and denying any OTG, you lose the brief wake-up throw invincibility from waking up off a knockdown.
You'd usually recovery roll every time you can but against characters with a strong command grab or proximity unblockable, staying on the ground to remove that move from the things you have to consider as you wake up is a viable option. An option that you don't have against Ex Robert's d~u+P proximity unblockable as it's bugged and moves that lead to a hard knockdown as opposed to soft.

Recovery Roll Speed

Characters have different recovery roll speeds. The differences are listed here:

(-F) Faster recovery roll

• (-7F) - Xiangfei, Krizalid
• (-5F) - Maxima, Kasumi, Angel
• (-3F) - Mai, Chris, Chang
• (-2F) - Whip
• (-1F) - Shermie, Leona
• (0F) - Kyo, Shingo, King, Kusanagi, Kyo-1, Kyo-2, Nameless, K', Athena, Yuri, Goenitz, Zero, Igniz, Geese
• (+1F) - Chin, Iori, Mature, Vice, Ralf, Clark, Ramon, Clone Zero
• (+2F) - Billy, Kula, Joe, King, Foxy, Omega Rugal
• (+3F) - Daimon, Takuma, Ryo
• (+4F) - Robert, Benimaru, Yashiro, Yamazaki, Vanessa
• (+5F) - Kim, Kensou, Terry, Hinako, Heidern, Jhun
• (+6F) - Bao, Andy, Seth
• (+7F) - Choi
• (+8F) - Lin, Mary
• (+9F) - May Lee

(+F) Slower recovery roll