Open big shapely hands at the One level

Take this hand: 
♠ 2
♥ A
♦ AKJ732
♣ AQJ32

Clearly it is a monster, easily worth 23 points. But if you open it 2 ♣ (showing any hand with 23 points), the auction is likely to get away from you. In the modern game, everyone likes to bid; when you have so much shape, you will rarely have an unopposed auction.

It is far better to open 1 ♦ , preparing to play catch-up next time. 'It might go All Pass,' do I hear you cry? No way — the other three players have 12 major-suit cards to divide between them. Someone will surely say something — and then you can jump in Clubs. By opening 1 ♦, you will better be able to describe your hand, allow partner better to describe theirs and generally get a more informed feel for the deal.

Exercise: what is your bidding plan with these
powerhouses?

(i) Open 1 ♣ and jump to 2 ♠ over a 1 /1 response. Opener jump rebidding in a new suit is forcing to game, showing a full 19/20 points, not a mere 16-17.
(ii) Open 1 ♠ then jump to 3 (forcing to game). Note that opening 1 then bidding spades is completely wrong: it shows more hearts than spades.
(iii) Open 1 and jump to 3 NT over any response, best played as gambling based on a good diamond suit, rather than a flat 19-point hand (rebid 2 NT with that).

Click to play this hand

West led ♦ J, which held the trick, then a hopeful ♦ 10. Declarer ruffed and correctly started on clubs. He cashed ♣ A and (not cashing ♣ K — key — or he’d be unable to ruff two clubs in dummy without East overruffing) ruffed ♣ 2 with ♠ 2. He led ♠ 4 to ♠ J, ruffed ♣ 4 with ♠ Q (East discarding), led ♠ 5 to ♠ AK and enjoyed ♣ KJ8, then ♥ KA. Twelve tricks and slam made.