[reisig]

2♣ Using 2♣ 2♦ 3♥ showing 4+♥ with longer ♦s is what I'd suggest.

[jdulmage]

You have a 4 loser hand, you have 8.5 quick tricks and need half a trick from your partner to make 3NT. Open 2♣ all day. If you and your partner don't have a partnership agreement for 3NT (you don't play it 25-27 and you don't play it gambling, you just don't play it period like my partner and I), then you could open 3NT and watch it pass out - this prevents the opponents from having any sort of chance to find a lead by doubling or bidding.

3NT is almost a given anyways, you have 2 sure clubs and either a heart or a spade for 3 tricks and 6 diamonds for 9 total tricks. If partner has 1 diamond for you, it is 35% that they will split and if he has 2 diamonds for you, it is 67% that it will break. The odds are good enough in IMPs.

Any other bid would be suicide.

[Kalvan14]

3NT is 2 off: 6 spades loosers on the lead (pard has 2 small spades). Good result, considering that 6♦ is a lay-down.

Sorry guys: no one has convinced me. I'll go on opening 1m this kind of hands.