[jdiana]

So, I was randomly Googling "self-splinter" this morning, as one does, and came across this general rule from BWS:

"Jumps:
(a) the default interpretation of an otherwise-undefined bid one level above a strength-showing force (e.g., one club - one diamond - one heart - three spades) is a splinter; . . ."

BWS also has this under After Our Major-Suit Opening - Opener's Rebids:

"One of a major — one notrump — rebid one level above a forcing reverse or jump-shift is an autosplinter (big one-suiter; shortness bid)."

If I were going to add this to my notes, would it be incorrect to rephrase it as:

The default interpretation of an otherwise-undefined double jump bid (or rebid) of a new suit is a splinter (or self-splinter), e.g., 1♣ - 1♦ - 1♥ - 3♠ or 1♠ - 1NT - 4♣. A self-splinter shows a big one-suiter with shortness in the suit bid."

This is how I think of splinters but I want to make sure I'm not inadvertently changing the meaning.

Also, what is the recommended strength for a self-splinter, i.e., what does BWS mean by "a big one-suiter"?

Thanks!

[DavidKok]

I think a fine generalization is "If a specific suit bid would be natural and forcing, higher (jump) bids in that same suit are splinters". Personally I play some fit jumps and other non-splinters here as well, especially in competition, but the idea is the same. The 1♣-1♦; 1♥-? auction is a tricky exception and not my first choice of an example auction.

Self-splinters are very rare. If you are interested I could go into a bit more detail, but three challenges they face include:

• On the example 1♠-1NT auction, responder is limited (in both strength and degree of fit, even if 1NT may have 3-card support). It is therefore very uncommon to find partner with a good fit with enough support outside a specific side suit, which is what a splinter looks for to find slam. If you don't think it's going to be slam, why not bid 4♠?
  
• Splinters make partner captain of the auction. They consume a lot of bidding space, and should therefore be very descriptive and comfortably let partner take control from here. Self-splinters therefore typically require a trump suit that plays well opposite a singleton or reasonably well opposite a void, in addition to having pretty narrow shape requirements and honour concentrations. All of this makes them very low frequency. Typically very strong hands want to ask rather than show, as the (presumed weaker) hand opposite has far less to share.
  
• Modern gadgets have reduced their frequency even more - people tend to prefer to use slow, possibly artificial, forcing bids on their strong hands. On the example auction Gazzilli is a popular choice.

I am not sure what the recommended strength for a self-splinter it. You need to be able to make slam opposite the perfect minimum, and set trumps opposite a singleton or void. On this example, maybe something like ♠AKQxxxx, ♥AQx, ♦KJ, ♣x or slightly weaker?