Trumpet connection

Black looks vulnerable  

A white cut at a looks like a good possibility, but it's impossible for Black to patch up both weaknesses in one move ... or is it?

Black is secure  

By playing , Black creates a trumpet connection, which protects both possible sites against a cut.

The trumpet connection is also called the lion's mouth, and consists of two tiger's mouths.

FCS

The trumpet connection is also called the tiger’s paw, possibly due to the resemblance to the paw pads of an animal like a cat.

Black is really vulnerable.  

A drawback with this shape is that it still leaves a peep at a or b. In many situations, the solid connection (either of the circles) may be better. Also, a solid connection in one place would mean a White cut in the other place would be caught in a ladder. The peeps will also rob Black of eye potential, which may be relevant in other situations. If both peeps are made and answered, a B2 bomber results.

In the example on the left, I think it will be a real struggle for Black to stay alive.

-- Morten Pahle

Dave Sigaty: In the case where there are three stones the peep will not work. Black has time to answer a peep by playing at d. If there are only two stones, Black must answer the peep by connecting. Similar shapes but a very different result.

binky? Surely the reason for preferring a solid connection is the minimisation of opponent's ko threats.