To my usage/understanding of the English term, yes. How about yours? And how about the corresponding Asian terms?

E.g I don't think is a throw in even though captured 4 stones as self atari is the essential flavour of the name, playing where some stones just got captured is not. Agree?

Click Here To Show Diagram Code

[go]$$W Position 1
$$ +----------
$$ | . . . . .
$$ | . X X . .
$$ | . X O . .
$$ | . X O , .
$$ | 1 X O . .
$$ | . O O . .
$$ | 2 . O . .
$$ | . O O . .
$$ | O X . . .
$$ | . X . , .
$$ | . . . . .
$$ | . . . . .[/go]

P.S. but not all self ataris are throw ins, only single stone self ataris that don't themselves capture (because taking a ko is not a throw in, though you can throw in into a ko shape to start a ko).

Click Here To Show Diagram Code

[go]$$W
$$ +----------
$$ | . . . . .
$$ | . X X . .
$$ | . X O . .
$$ | . X O , .
$$ | 1 X O . .
$$ | . O O . .
$$ | 2 . O . .
$$ | . O O . .
$$ | O X . . .
$$ | . X . , .
$$ | . . . . .
$$ | . . . . .[/go]

I would call a nakade (inside play).

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

Visualize whirled peas.

Everything with love. Stay safe.

I agree. Dwyrin uses the term very widely and it's funny to my ears every time. He seems to use it for nakade but also I think sometimes just invasions and reductions.

According to my definition in [15],

"A throw-in is a player's crosscutting string that the opponent needs to remove to connect strings of his group",

a throw-in need not be a self-atari.

Your move 2 is a 'double threat to create a throw-in'.

https://senseis.xmp.net/?ThrowIn

SL is not explicit on the matter but all three examples are 'self atari'.

Like so many things, SL overlooks something, e.g. iterative throw-ins, for which some can be useful if they do not start with self-atari.

The assumption here seems to be that throw-in is a technical term. In Japanese, the direct equivalent, hourikomi, is not - at least according to Hayashi Yutaro or the Nihon Ki-in lexicon. It is just a descriptive word that is part of the ordinary language, and is used for things like chucking paper into a waste-paper basket.

It is common in Japanese go texts, but when a formal word is needed the one to turn to is uchikaku. This is very definitely a technical term and not part of the normal language. It's not even given in Kojien. For that reason, probably, it is not all that common.

Its definition is not so much in terms of a shape (e.g. self-atari) but of its function, which is to exploit defects in the opponent's eye shape by using sacrifice stones at the points of contact between each side's groups, in order to kill a group by squeezing it to death, or, failing that, just to capture some stones by oi-otoshi or to squeeze a group into horrible shape.

The use of "sacrifice stones" may or may not imply self-atari, and it may also be debatable whether every hourikomi is also an uchikaki move.

The "iteration" point made by Robert is also covered in Japanese by the word kuwaseru, to "feed in," which is ordinary Japanese, of course, but usually has to be explained in a go context, and so in that sense can be considered a technical term.

In Bill's example, I think the favoured Japanese term would be oki. Nakade tends to be reserved for moves inside a larger "nakade shape" (i.e. one where the defender could make two eyes, or a "bulky" one as James Davies would have it). But nakade can be used in other ways, especially of an endgame tesuji move inside an otherwise safe enemy territory.

As always here, we are seeing too much of a "mathematical" bent. Rather than seeking definitions it is often better simply to understand usage instead, and so remain flexible.

Self-atari can be used as a shape word or a technical or functional term.

One might want to a) observe and understand informal usage or b) seek definitions to enable replicated application for desired functions. (Mathematical precision of definitions are needed for unambiguity in all cases.)

I agree. Thanks.

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

Visualize whirled peas.

Everything with love. Stay safe.

According to Eba ( http://www.h-eba.com/heba/tumego/tsukamoto/tsuyo12.html ), may be called uchikaki. (At least, if it killed or threatened to kill the White group.)

Click Here To Show Diagram Code

[go]$$W
$$ +----------
$$ | . . . . .
$$ | . X X . .
$$ | . X O . .
$$ | . X O , .
$$ | 1 X O . .
$$ | 4 O O . .
$$ | 2 . O . .
$$ | 3 O O . .
$$ | O X . . .
$$ | . X . , .
$$ | . . . . .
$$ | . . . . .[/go]

I doubt if we would call it a throw-in, however.

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

Visualize whirled peas.

Everything with love. Stay safe.

For the move I showed, I wouldn't call it a nakade, both because that's not a term I use, and because like John said I thought it only applied to vital points of big eyes which the opponent could play to get 2 (or more) eyes, not a single one. As a noun I'd call it a placement, or as a verb probably just "black takes the eye" about its function rather than shape.

Saying a throw-in was self-atari on a single stone was probably too restrictive as I suppose this is probably a throw-in?

Click Here To Show Diagram Code

[go]$$W Position 2
$$ | . . . . . . . . . .
$$ | . . . , O . O . O ,
$$ | . . . O . . . . O .
$$ | . O . O X X X X O X
$$ | . . X X 1 O . . X .
$$ +--------------------[/go]

Or this leading up to snapback:

Click Here To Show Diagram Code

[go]$$W Position 3
$$ -------------
$$ . . . . . . .
$$ . O O O O O .
$$ . O X X X O .
$$ , O X . X O ,
$$ . O X O X O .
$$ . O X 1 X O .
$$ . O O X O O .
$$ . . . X . . .
$$ . . . . . . .[/go]

Which we can then extend to the non-self atari version with the same function of denying opponent a solid connection needed to make a real instead of false eye, is this still a throw-in?

Click Here To Show Diagram Code

[go]$$W Position 4
$$ -------------
$$ . . . . . . .
$$ . O O O O O .
$$ . O X X X O .
$$ , O X . X X O
$$ . O X O . X O
$$ . O X 1 X X O
$$ . O O X O O O
$$ . . . X . . .
$$ . . . . . . .[/go]

@Mike, calling an invasion or reduction a throw-in seems pretty wacky, unless it's as a phrase like "let's throw a stone in his moyo and see what happens".

Without searching, my instinct is that I see "throw-in" (and, in older books, "horikomi") used only for self-atari of a single stone. If it's not self-atari, then to me it's a placement, not a throw-in.

Click Here To Show Diagram Code

[go]$$W Position 2
$$ | . . . . . . . . . .
$$ | . . . , O . O . O ,
$$ | . . . O . . . . O .
$$ | . O . O X X X X O X
$$ | . . X X 1 O . . X .
$$ +--------------------[/go]

Good example! Personally I wouldn't call it a throw-in, but I don't have another single word name for it either. (Taking the term perhaps too literally, when I throw a ball, it travels on its own, it's not attached to another ball. This feels more like a push or an extension.) I'd say something like: pokes out black's eye (or perhaps makes a false eye, but then we can have another discussion about the definition of "false eye"!)

IIUC, these plays would be called uchikaki. We might call them eye-stealing sacrifices, but eye-stealing tesuji is already taken.

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

Visualize whirled peas.

Everything with love. Stay safe.