Opening Bid: Two Clubs - 11-16 HCP
This is an opening bid that is frequently used in all strong club systems... It shows an opening hand with a club suit. Players often modify it with different agreements, but the most common way of playing it is to have 11-16 HCP and at least a 5-card club suit. Some players prefer to promise a 6-card suit, but that agreement restricts the use of the bid. The opener may have a 4-card major.
Responding to an Opening Bid of Two Clubs
If responder uses the 2 asking bid and then rebids a major at the 3-level, the bid is natural with at least a 5-card suit and is forcing. (An immediate jump to the 3-level in a major is only invitational.)
Negative Double by Opener
Negative doubles are almost always used by the responder in a competitive auction, but it can be used by either partner after an opening bid of 2. If you are the opener, and your partner asks about a major by bidding 2, you might get an interference bid on your right. If they overcall with a major, you can double, promising the other major. If they overcall with a diamond bid, you can double to show both majors. (With only one, you should just bid it.) Partner is allowed to convert the negative double to penalty.
A jump to 4 by responder may appear to be a jump raise, but it's Gerber, asking for keycards. There are five key cards... four aces and the K, with only three kings.
Four Diamonds - Five Clubs
With four diamonds and five clubs, opener should start with a 1 call and then rebid 2.
Five Diamonds - Five Clubs
With 5-5 in the minors, we use an opening bid of 3NT to show that hand. Most other club systems prefer a 2NT call, but we use that bid to show both majors. 3NT Opening Bid