He had to lead away from the heart king at the end, so lost one diamond and two hearts.
He lost two spades, one diamond and one club.
Now it looked as if declarer would fail, losing one spade, one diamond and two clubs.
Now declarer lost only two hearts and one diamond for minus 300.
After the diamond-king opening lead, East lost one heart, one diamond and one club to make his contract for plus 420.
Superficially, South was due to lose one heart trick, one diamond and two clubs.
He would have lost only four spades and one diamond, his heart loser disappearing on the board's club nine.
South loses two spades, one diamond and one club.
Now declarer made his contract, losing three clubs and one diamond, for plus 400.
Declarer had to lose two hearts and one diamond, going down one.