The Rule of 2, 3 and 4

The Rule of 2, 3 and 4 is a guideline for opening with a weak two bid depending on the vulnerability.

Rule of 2

At unfavorable vulnerability (red on white), the recommendation is to be 2 tricks shy of a 2-level contract. In other words, opener should have 6 tricks to open a weak two bid.

Example:

AKQT54 5 987 654

This is the classic example of a weak two. There are 6 probable spade tricks, and it can therefore be opened 2.

Rule of 3

At equal vulnerability (white on white or red on red), the recommendation is to be 3 tricks shy of a 2-level contract. In other words, opener should have 5 tricks to open a weak two bid.

Example:

65 KQJT87 843 52

There are 5 probable heart tricks, and it can therefore be opened 2.

Rule of 4

At favorable vulnerability (white on red), the recommendation is to be 4 tricks shy of a 2-level contract. In other words, opener only needs 4 tricks to open a weak two bid.

Example:

JT9874 5 AT8 987

3 spade tricks + 1 diamond trick = 4 tricks. At favorable vulnerability, this hand can therefore be opened 2.