Here I will break down Sasori's combos, uses and some tips on which attacks you can link them with...
Neutral:
----21 hits
----SB
----Last hit is a iron sand projectile which pins the opp.
----If they KNJ mid way and rush towards you, the iron sand projectile will knock them down.
----If opponent is out of chakra... neutral combo > SB > U2.
----If it doesn't goes into SB, you can link it with c. kunai or air U1 (which comes out faster than the ground U1)
----Opp loses chakra if they don't tech nor goes into SB.
----It can be canceled with U1, kunai/c.kunai, grab or air dash. (I recommend c. kunai)
Side:
----16 hits
----SB
----If opponent is out of chakra... side combo > SB > U2.
----If it doesn't goes into SB, you can link it with c. kunai or air U1 (which comes out faster than the ground U1)
----Opp loses chakra if they don't tech nor goes into SB.
----It can be canceled with U1, kunai/c.kunai, grab or air dash. (I recommend c. kunai)
Down:
----13 hits
----SB
----If opponent is out of chakra... side combo > SB > U2.
----If it doesn't goes into SB, you can link it with c. kunai or air U1 (which comes out faster than the ground U1)
----Opp loses chakra if they don't tech nor goes into SB.
----It can be canceled with U1, kunai/c.kunai, grab or air dash. (I recommend c. kunai)
Up:
----14 hits
----No SB
----Leaves opponent in the air.
----Can link with U2 if opp doesn't air tech.
----You can link it with c. kunai or air dash/combo/item.
----Opp loses chakra if they don't tech.
----It can be canceled with U1, kunai/c.kunai, grab or air dash. (I recommend c. kunai)
Air:
----9 hits
----Thee most effective way to land an Air combo is after an air dash.
----Opp loses chakra OTG.
----Link with c. kunai > dash > tilt loop! XD
----Hard to KNJ.
----Untechable.
----Best combo string!
----If opp KNJ's, KNJ back and poison tag > c. kunai. Or simply ball bomb.
----When opp ninja moves and shuriken spams, block while positioning the puppet close to them and then air dash...
----Can tech chase with air dash > combo if timed well.
----Can be also linked with item.
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It would have been a waste of time to do a Sasori guide after cinik's awesome contribution, so I just wanted to add his combo strings info.