Yun-seong's fastest moves?

[shot040]

Hello, i'm looking at this chart http://8wayrun.com/wiki/yun-seong-frame-data-sc4-bd/ and I don't understand. Where it says IMP does that mean how fast the move comes out? I'm talking about SC4 btw. What are Yun-seong's fastest moves to counter a spammer?

 

[KineticClash]

The ones with the (?) are fastest. Too fast to quantify, in fact.

 

[NDK]

Yes, IMP refers to the speed of the move, the lower the number the faster the move

 

[shot040]

Ok and what is good to counter spammers. The only thing I can really use is KKB the other being WR B.