P3

From Simplex

PRINCIPLE 3: A 6+ card suit can also be opened at the one-level if it satisfies the criteria for such a bid. (This overlap in the ranges for an opening bid helps to keep the bidding low while the partners search for a fit. In practice this means that a two-level opening bid will contain 3-8 HCP, because on any more, the hand would satisfy the criteria for a one-level opening. Two-level overcalls, on the other hand, occupy the full range 3-16 HCP, because opposition bidding will often force a two-level bid.)