I just played a sequence analog to the following in a 9x9 game:

Click Here To Show Diagram Code

[go]$$ Black splits White
$$ . . O . X . O . .
$$ . . O . X . O . .
$$ . . O . X . O . .
$$ . . O X X X O . .
$$ . . O 2 5 4 O . .
$$ . . . 1 O 3 . . .
$$ . . . 7 6 . . . .
$$ ----------------[/go]

Is this a tesuji? Does it have a name?

It is certainly a well-known tesuji but I never seen that it has a name.

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Still officially AGA 5d but I play so irregularly these days that I am probably only 3d or 4d over the board (but hopefully still 5d in terms of knowledge, theory and the ability to contribute).

It is known as the "two stone edge squeeze" or "stone tower" tesuji. See this Sensei's Library page for more information: http://senseis.xmp.net/?TwoStoneEdgeSqueeze

Although that was also my thought at a cursory glance, it's not what is shown. It is simply what I would describe as cutting a double knight's move on the 3rd to 2nd line. Here are the key stones from which I expect a ~15 kyu or stronger to realise it is cut.

Click Here To Show Diagram Code

[go]$$ Black splits White
$$ . . . . . . . . .
$$ . . . . . . . . .
$$ . . . . . . . . .
$$ . . . X X X . . .
$$ . . O . . . O . .
$$ . . . 1 O . . . .
$$ . . . . . . . . .
$$ ----------------[/go]

is a jump attachment. is a clamp. - capture White in a ladder.

The whole operation may be called a scissors. That term is not in common use in English, but I saw it (in Japanese, OC) in an old copy of the problem classic, Gokyo Shumyo. (See http://senseis.xmp.net/?GokyoShumyo )

Congratulations on seeing it!

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At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

Thanks.