Transfer and Shape Bids over Strong Club
Transfer and Shape bidding after opponents open a strong NT or strong 1♣ (precision) hand.
An overview reminder of TRaSh against opponents opening a strong 1NT.
All the reasons we want to compete against opponent's opening 1NT exist when strong club players open 1♣. Typically, precision (and variants) use the 1♣ bid as an artifical bid with all hands that are 16+ HCP or very strong playing strength (aka long 1 suited hand).
Statistical analsys shows that the vast majority of those opening 1♣ hands are balanced hands with approximately 17 HCP. As with interfering against opponent's 1NT, there is little profit in allowing the opponents to have an unconstested strong 1♣ auction.
The safest hands to compete agains the strong ♣ are similar to the ones we selected to compete against the strong 1NT. That being single suited hands and two-suited hands. We'll apply a similar rule of 8 in our decision making. The Rule of 8 for competing states that we compete against the strong hands when we have at least 6 HCP AND 2 more cards in our two longest suits than our Losing Trick Count.
Using the concept that we need to single suited hands and two suited hands. We reserve the one-level bids for two-suited hands. That keeps the bidding level lower for us to correct to the best possible fit and determine whether we should defend or sacrifice in the hand. For the many reasons discussed in the Modern American approach, we like transfers. A transfer allows the bidder to retain the control in the auction. So, we use the 2-level biddings as a transfer request to the next higher suit. It doesn't make sense for the bid of 1NT to be natural, in consideration that the opener is showing a very good HCP hand. So, 1NT is a transfer to clubs. This keeps us from having 2♠ as the transfer request and driving the auction up to the three-level. 1NT over opponent's 1♣ is sufficient interference to make their life difficult.
Transfer Bids after strong 1♣
1NT -> clubs
2♣ -> diamonds
2♦ -> hearts
2♠ -> spades
Two-suited bids after strong 1♣
Dbl - both Majors
1♦ - three suited hand and at least 13 HCP
1♥ - Hearts and minor suit
1♠ - Spades and minor suit
Finally, there is no reason you can't interference at the 3 or 4 level with extrememly long, preemptive hands. If you would preempt with your hand normally, you can jump in at the higher level. You will probably have a hand more suited (no pun intended) to a sacrifice. Don't forget about the Rule of 2/3/4 of preempting before wading in, you have some knowledge that all the HCP in the opponents hand, so you are less likely to get lucky like normal preempts in finding a trick or two with partner.
So, what about hands with both minors? This is discussed in the linked article
We find litte benefit in trying to find minor suit fits with both minors, but if you have a strong(ish) hand with both minors (perhaps 6-5 shape or better). The bid of 2♠ or 2NT could be adopted to show minor suit holding. This is definately some to discuss with your partner. It will rarely come up, and has great potential to be forgotten. We suggest using 2♠ for hands with 6-5 in the minors and 2NT for hands with exactly 5-5 shape. The 2♠ gives some room for partner to bid 2NT to ask opener to bid their 6 card minor. Useful when holding equal length/strength and letting parnter decide where they would like to play.
Bidding The three suited hand is discussed in the linked article.
The three suited hand: The interference of 1♦ over opponents 1♣ is not really interfering at all. Opponent can simply double to state they would have bid 1♦ (generally a weak response to the opening 1♣) and Pass with some values (but no other quality to mention). They can freely bid any other bid that they would have made without the 1♦ interference and it would have their usual systematic meaning. Therefore, we use the 1♦ overcall in a very specific case, a three-suited hand and opening/near opening HCP. This serves a couple of purposes. In this situation, it is likely