[gprentice]

At my club there seem to be a variety of situations when people open a strong 2C. For some people it's a game force where you want to be in game regardless of your partner's hand. Some people it's 20+ unbalanced or 23+ balanced. Some people it's 8 playing tricks. Some people it's 4 losers. Some people it's the rule of 29 - sum points plus length of two longest suits being 29 or more.
e.g.
nz bridge beginner lessons

Playing two over one what is the "best" or optimal way to play the 2C opening.
Should you have an "escape system" where responder can pass before game is reached.

If you have a 25 point balanced hand, should you rebid 3NT instead of 2NT so that you partner can pass 2NT with no points. I've been told not because it denies responder a chance to bid stayman or transfers.

[Cyberyeti]

Best solution to balanced hands is Kokish or birthright (same thing, alternative names).

2♣-2♦-2♥(hearts or bal)-2♠(pretty much forced)-2N is balanced stronger than 2♣-2♦-2N, hands with hearts bid something other than 2N.

You should play some system over 2♣-2♦-3N, what you can't do is play puppet.

[apollo1201]

The question about 2C GF or not (and.can we stop before game) partially depends on what you do with the following strong hands but not quite stirring enough to be GF on their own (ie 24+ bal or 9 tricks in M, 10 in m)

- a one suiter such as game minus 2

AQJTxx
Kx
AQx
Axx

Opening 1S risks a general pass while partner with some 4-5 HCP hands makes game a good bet (SK and a minor doubleton, the HA and a fit, DJ plus something useful, etc.). Still with 0 opposite 2S is the max.

- 22-23 bal if your NT ladder is 2NT = 20-21

Some systems have 2 strong openings, one GF and one not GF, but lose some offensive bids at the 2 level. There is always a trade off somewhere.

2C ambiguous allows to stop but multiple systems exist (2D positive, 2D waiting and cheaper minor negative, etc.).

In all cases, the 2C opening should have enough defensive values on the side, to go back to your question.

For example, AKQ 10th of H and out is indeed 2 tricks more than the almost GF hand I posted above; and produces game on its own, but it is definitely not a 2C opener.

For unbal hands, a not too quacky 16 is probably the minimum.

There are also legal constraints to respect.

[DavidKok]

I've shared my thoughts on this topic at length before. If you're interested, I invite you to look for the older posts. Instead I will keep it brief this time.

• 2♣ is a necessary evil in standard systems. Almost always when you open it, you have a tough auction after. It is a good idea not to open it voluntarily if you have reasonable alternatives.
  
• Back in the day people were cowed by the strength of 2♣ and would let you have the auction uninterrupted. These days this is false, even at lower levels. Be very careful making a strong nebulous jump opening bid if you're bidding based on shape - you might find yourself at an uncomfortable level on a contested auction before it gets back to you.
  
• All the advice about 'we can make game opposite the right 3-count' and the likes is a tremendous trap. Be very careful if people start presenting brilliant hands to convince you not to open at the 1-level. With strong hands you are taking a risk either way - the name of the game is taking the lesser one. Usually, partner doesn't hold the perfect minimum - either more or less and a 1-level opening works just fine. Plus, sometimes the opponents rescue you even if partner passes - especially if you're bidding on shape.
  
• For this reason I strongly prefer that a 2♣ opening shows about 22 hcp. Some decent 21-counts or even magnificent 20-counts are fine - hand evaluation is not about points - but I have to communicate about my actual high card point preference somehow. My experience is that with slightly weaker hands, in the 19-21 range, opening at the 1-level is the lesser risk (and the even weaker shapely stuff is a no-brainer to me). For this reason I also play that 2♣ is either forcing to game or specifically lets us stop in 2NT. The extra bidding space freed up by knowing partner cannot drop us helps find the right games or slams in the rare cases where we do need to rely on the fragile strong opening. What's more, without this it is nearly impossible for partner to evaluate their hand. Jumping on strong hands is usually bad. Jumping without saying anything about your shape is even worse.
  
• Be aware that a lot of people absolutely love opening their gadget, and there's no universal standard for the 2♣ bid. I always feel a bit uncomfortable when people are bemoaning the regulatory definitions and restrictions on 2♣, as I wouldn't wish to make such an awful self-preemptive opening bid with anything near the minimum of what the rules require.

[barmar]

It's practically never necessary to open 2♣ on weaker hands just because you have a long, strong suit. If you have a freak, it's likely someone else also has a long suit or shortness in your suit, so the auction won't stop if you just open your long suit.