Suggested Solution

South has 8 top tricks so needs just 1 more to make the contract. You as declarer can see that the defenders can probably make at least 4 spade tricks and 1 diamond trick before you can make nine tricks. However, if you can convince East that you hold 3 spades you may just pull it off. Normally with an Ace doubleton opposite three cards in the critical suit, you would win straight away as the rule of "seven" is not applicable. However, if you hold up and play the 2ª , East may consider that you hold 3 cards in spades and switch to a diamond because leading a spade will give you two tricks in the suit.