First Answer
Partner is on lead against one notrump.
Partner leads the three of spades (six, ten, five). You return the Jack (Ace, two, eight). What’s going on in spades? Partner started with five spades (led the three and played the two on the next round) so declarer started with three. Declarer must have started with the AK5 (declarer would have held up again from an original Axx). Bonus from Val: This is not a 100% inference; not every declarer plays correctly. However, it’s a strong inference.
Declarer cashes four rounds of hearts (declarer started with AK7); partner discards the ten of clubs followed by the four of diamonds.
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