There are legspinners and there are left-arm wristspinners. While both ply the same craft, albeit with a different arm, they are treated and viewed differently. Familiarity is a highly underrated virtue and a decent left-arm wristspinner spinning a web around batsmen highlights that. The same variations bowled by a legspinner don't seem to have the same mystery as compared to a left-arm wristspinner. Kuldeep Yadav, the first left-arm wristspinner to play for India in Tests, used his variations to great effect on the first day.
At the outset, there are two things that work in his favour - his short stature, which allows him natural dip. Taller bowlers find it difficult to create the parabola loop and therefore, have to work really hard to get the ball to dip on the batsman. Some of Kuldeep's deliveries land a touch shorter than where the batsman expects them to fall. The other key difference is his unique angle from over the stumps. He forces right-handed batsmen to open their stance - to take care of the blind spot outside the leg stump - and that in turn is testing the batsman's footwork more. Now, they have to plant the foot a little straighter and play inside the line for deliveries pitching within the stumps, and yet be mindful that they don't go too straight as some might hold the line and go across with the angle. Also, there's a demand to have a bigger front-foot stride going across to the ones that pitch a little wider outside off.
David Warner
While facing Kuldeep, batsmen often misread full balls for short ones, like David Warner. Since the trajectory is quite low, you mistake normal falls for faster and shorter deliveries. He went back to a ball that was too full and too close to cut. My coach Tarak Sinha would tell us to avoid playing an attacking shot when an error - misreading the line or length - is committed. That would add to the first mistake, and batting doesn't let two errors go unpunished. Kuldeep's biggest strength on the first day was the cluster he created, which highlighted that he bowled a lot fuller than any other spinner in the series. Bowling it full forced the batsmen to play offensive shots, thereby creating possibilities of committing errors. Also, his length took the flat nature of the pitch out of equation, for he was no longer reliant on a positive response from the pitch to create doubts. Kuldeep has two different legbreak deliveries; the one that dismissed Warner was bowled with the seam going across the pitch.
Peter Handscomb
The other variety of Kuldeep's legspin dismissed Handscomb: this one was bowled with a scrambled seam which caused the ball to spin sharply after pitching. The sequence of deliveries that led to Handscomb's wicket highlighted Kuldeep's guile in weaving a trap. He bowled a flatter googly that stayed low. Handscomb went back and missed it by a fair distance. Kuldeep flighted a few deliveries to which Handscomb responded by stepping out and reaching the pitch of the ball, which he successfully managed a few times. Then Kuldeep bowled one wide of the off stump, luring Handscomb into playing an expansive drive. This time the foot was nowhere close to the ball - due to the angle created by bowling over the stumps - and the ball sneaked through. A tactic for Kuldeep could be to start leaving the cover area vacant to invite more such shots.
Glenn Maxwell
Except Steven Smith and Matthew Wade, most Australian batsmen failed to read the spin from Kuldeep's hand. Therefore, they were trying to read it off the pitch, which led to playing more off the back foot, even to deliveries that should've been played off the front foot. Maxwell has a tendency to stand on the leg stump and staying besides the ball. This allows him to create extra room, which is an asset in limited-overs cricket, but that works against him in Tests. The ball that dismissed him was bowled from the back of the hand and since Maxwell didn't have a second line of defense, it crashed into the stumps. It was quite obvious that he didn't read the spin from the hand and hence ended up playing down the wrong line.
Kuldeep's first bowling performance in Tests was quite impressive, for picking wickets on a first-day pitch is always tough for a spinner. Since his optimum speed is a little slower than both Ashwin and Jadeja, it'll be interesting to see if and how the slowness of the pitch impacts his bowling in the second innings of this Test.