An opening two of a minor is non-forcing and shows a hand with at least six cards in the bid minor and opening values – a nominal minimum strength of 12 points and rule of 20. There may be four cards in the other minor, but with five open 2NT.

In first and second hand, there won't be a four-card major side-suit. In third position, the long minor may be only five cards and now it is acceptable to suppress a four-card major if you judge the pre-emptive effect of the two-level opening to be more valuable.

There is no scrambling and no minor relays after a minor two opening. All responses and continuations are systemic neutral bids – in particular, 2NT is fit agreement. Suits are bid upwards regardless of length, but taking account of opener's denial of a four-card major. Bidding can stop in three of opener's suit, but is otherwise forcing to 3NT, so any constructive response will be invitational-plus.

WestNorthEastSouth
2pass
4
A pre-emptive fit bid.
WestNorthEastSouth
2pass
2NT
Strong agreement of diamonds.
WestNorthEastSouth
2pass2pass
2NT
2 shows five+ hearts, invitational-plus and forcing. 2NT agrees hearts.
WestNorthEastSouth
2pass
2pass3pass
4pass4pass
5passpasspass
2 shows four+ diamonds, invitational-plus and forcing. 3 shows a maximum opener (otherwise 3) with no three-card major (otherwise 2 or 2), no diamond fit (otherwise 2NT) and an empty suit: opener is probably 2236. 4 is a forcing suit-setter, and 4 says 'nothing more to say' (see Fit Bidding).
WestNorthEastSouth
2pass
2pass2pass
3passpasspass
2 showed three cards, forcing. 3 is nothing more to say: three of opener's minor is the only stopping place below game after responder bids.
WestNorthEastSouth
2pass
2pass3pass
3
3 showed four cards, forcing. 3 is a forcing suit-setter with less than a solid suit (otherwise 3 immediately).
WestNorthEastSouth
2pass2pass
2pass3pass
4
A forcing suit-setter (must be 3064).

NEXT: competition in a neutral auction