Sevens Rule
Sevens Rule Definition
The Sevens Rule applies only to California Lowball. It is simply:
After the draw, if you have a seven or better, you may not check it.
For the purposes of the Sevens Rule, calling an amount that is less than the post-draw bet size is considered a check. The only way that can happen is if the first player to bet goes all-in for less than the post-draw bet size.