A hajiki Screw ("flick SPD") motion lets you do a Spinning Pile Driver or Mexican Typhoon extremely quickly, and it's ideal for grabbing whiffed low kicks. More explanation below but first a quick 2ch note.
I've been reading about the hajiki Screw technique on 2ch for a long time, but based on context I thought it simply referred to a quick walk-in SPD. Also the term comes up most commonly when people are saying silly stuff about Rikiya so I never paid much attention.
One night at Versus, VIPER kindly explained the motion to us Yanks. To do a hajiki Screw you give the joystick a small but firm flick in a circular direction and tear your hand away allowing the spring to carry it around. For 1P side you start with the joystick right and flick it clockwise. For 2P start at left and flick counter-clockwise.
It might sound a little alien but this motion isn't very difficult. VIPER said it took him twenty minutes practice to get the hang of it on one side and about an hour on the other. Your humble blog editor was able to do a hajiki Hyper Bomb almost immediately. You can try it on the character select screen: with a proper hajiki motion the highlight rectangle should go around and land where it started.
Do not practice Flick SPDs on your laundry!
VIPER said the motion is easier on a looser (broken-in) stick. He didn't mention this, but I'd speculate that it's easier on Seimitsu than on Sanwa — dead zone is a little different — but it's definitely possible on both.
Here's a quick video of VIPER demonstrating the hajiki Screw. First for 1P side then for 2P side.
I asked if Pony used hajiki Screw and Shu (Ken player) laughed and said no but he said Gunze and most Hawks use it. Shu said that when a Zangief player uses it well vs. whiffed Shoto low medium kick and low roundhouse the match starts to get unwinnable. Daigo supposedly said as much after losing to Rikiya thirty times in a row.
Here's one more video of an actual match. Attempted Hajiki early in the second round. The YouTube interface covers it up; you have to mouse away to see it.