EDIT: This post is very detailed and technical. For a smaller post with all of the most important information, read this: http://testyourmight.com/forum/showthread.php?12173-List-of-characters-who-can-crouch-crouch-block-under-f-1-amp-f-11&p=184436&viewfull=1#post184436
While playing online I noticed that sometimes people seemed to be crouching under my f+1 and f+11, making them whiff completely even when blocking low. I've gone into training mode and it turns out, unfortunately, it wasn't just online wackiness. Also, this game has some of the most screwed-up hit detection I've ever seen. Check out the number of categories below to see what I mean!
Here is the full list of characters for each category:
Can crouch AND crouch block under f+1 & f+11:
Kung Lao
Mileena
Johnny Cage (NOTE: his crouching hitbox moves upward very rarely, in which case f+1 will connect. don't count on it!)
Jax
Can crouch under f+1 & f+11, can crouch block under f+11, can crouch block under f+1 at close range but not from f+1 max range:
Kitana (not too strict on the distance here)
Reptile (way too strict to be practical, must be absolute max range. also has the same crouching hitbox weirdness as Cage)
Cannot crouch under f+1, can crouch under f+11, can crouch block under f+1 & f+11:
Quan Chi (up & down crouching hitbox, f+11 can occasionally hit crouch)
Cannot crouch under f+1 OR f+11, can crouch block under both f+1 & f+11:
Sektor
Cannot crouch under f+1 OR f+11, can crouch block under f+11 unless in the corner, f+1 randomly whiffs sometimes on crouch block:
Skarlet
Cannot crouch under f+1 or f+11, cannot crouch block under f+11, f+1 randomly whiffs quite a bit on crouch block:
Sub-Zero
Can crouch but NOT crouch block under f+1 & f+11, though both moves can randomly whiff on crouch block in the corner:
Ermac (another character with a crouching hitbox like Cage, as well)
Cannot crouch OR crouch block under f+1, can crouch under f+11, can crouch block under f+11 unless in the corner:
Cyrax (NOTE: his crouching hitbox also varies, in the opposite way of the other characters mentioned; on very rare occasion, f+1 will whiff)
Cannot crouch OR crouch block under f+1, can crouch and crouch block under f+11:
Sonya
Kano (f+11 sometimes connects on crouch due to, again, rising hitbox. more common than a lot of the others but should still stick with f+1 alone)
Cannot crouch OR crouch block under f+1, cannot crouch under f+11, can crouch block under f+11:
Kabal
Cannot crouch OR crouch block under f+1, cannot crouch under f+11, can crouch block under f+11 unless in the corner:
Smoke
Cannot crouch OR crouch block under f+1 or f+11, though f+1 can randomly whiff on crouch block in the corner:
Nightwolf
Cannot crouch OR crouch block under f+1, can crouch but NOT crouch block under f+11:
Jade
Freddy Krueger
IMPORTANT NOTE: These characters cannot crouch f+11 immediately after blocking f+1, so for practical purposes this group is just as good for us as the one below.
Cannot crouch OR crouch block under f+1 or f+11:
Scorpion
Liu Kang
Sindel
Noob Saibot
Stryker
Shang Tsung
Raiden
Sheeva
Cyber Sub-Zero
Kenshi
Rain
While playing online I noticed that sometimes people seemed to be crouching under my f+1 and f+11, making them whiff completely even when blocking low. I've gone into training mode and it turns out, unfortunately, it wasn't just online wackiness. Also, this game has some of the most screwed-up hit detection I've ever seen. Check out the number of categories below to see what I mean!
Here is the full list of characters for each category:
Can crouch AND crouch block under f+1 & f+11:
Kung Lao
Mileena
Johnny Cage (NOTE: his crouching hitbox moves upward very rarely, in which case f+1 will connect. don't count on it!)
Jax
Can crouch under f+1 & f+11, can crouch block under f+11, can crouch block under f+1 at close range but not from f+1 max range:
Kitana (not too strict on the distance here)
Reptile (way too strict to be practical, must be absolute max range. also has the same crouching hitbox weirdness as Cage)
Cannot crouch under f+1, can crouch under f+11, can crouch block under f+1 & f+11:
Quan Chi (up & down crouching hitbox, f+11 can occasionally hit crouch)
Cannot crouch under f+1 OR f+11, can crouch block under both f+1 & f+11:
Sektor
Cannot crouch under f+1 OR f+11, can crouch block under f+11 unless in the corner, f+1 randomly whiffs sometimes on crouch block:
Skarlet
Cannot crouch under f+1 or f+11, cannot crouch block under f+11, f+1 randomly whiffs quite a bit on crouch block:
Sub-Zero
Can crouch but NOT crouch block under f+1 & f+11, though both moves can randomly whiff on crouch block in the corner:
Ermac (another character with a crouching hitbox like Cage, as well)
Cannot crouch OR crouch block under f+1, can crouch under f+11, can crouch block under f+11 unless in the corner:
Cyrax (NOTE: his crouching hitbox also varies, in the opposite way of the other characters mentioned; on very rare occasion, f+1 will whiff)
Cannot crouch OR crouch block under f+1, can crouch and crouch block under f+11:
Sonya
Kano (f+11 sometimes connects on crouch due to, again, rising hitbox. more common than a lot of the others but should still stick with f+1 alone)
Cannot crouch OR crouch block under f+1, cannot crouch under f+11, can crouch block under f+11:
Kabal
Cannot crouch OR crouch block under f+1, cannot crouch under f+11, can crouch block under f+11 unless in the corner:
Smoke
Cannot crouch OR crouch block under f+1 or f+11, though f+1 can randomly whiff on crouch block in the corner:
Nightwolf
Cannot crouch OR crouch block under f+1, can crouch but NOT crouch block under f+11:
Jade
Freddy Krueger
IMPORTANT NOTE: These characters cannot crouch f+11 immediately after blocking f+1, so for practical purposes this group is just as good for us as the one below.
Cannot crouch OR crouch block under f+1 or f+11:
Scorpion
Liu Kang
Sindel
Noob Saibot
Stryker
Shang Tsung
Raiden
Sheeva
Cyber Sub-Zero
Kenshi
Rain