Exa. 1.3  

Comments on Definition 1

A general term for connecting strings is useful. The name "string connection" is better than the name "solid connection" because

• string connection expresses exactly what it means: strings are connected,
• solid in solid connection can be confused with other usage of "solid".

Definition 1 allows both bad moves like in Exa. 1.2 and good moves like in Exa. 1.3.

Definition 2: Joining Previously Cuttable Stones

Solid Connection Page Version 18

In solid connection page version 18, the user 62.237.44.16 aka Bass defines: "A Solid Connection is a connecting technique that joins previously cuttable stones to each other so that there is no gap between them. Because all the stones now belong to the same chain, the stones connected this way can never be separated from each other again."

Chain is the same as string. "so that there is no gap between them" equals "all the stones now belong to the same chain". "the stones connected this way can never be separated from each other again" equals "all the stones now belong to the same chain". "is a connecting technique" does not provide relevant information in this context. Therefore the definition can be written shorter as follows:

"A solid connection forms a string by joining previously cuttable stones to each other.

For greater precision, "forms a string" can be replaced by "string connection":

"A solid connection is a string connection joining previously cuttable stones to each other.

Examples of Definition 2

Exa. 2.2  

Counter-example of Definition 2

Counter-exa. 2.3  

According to definition 2, this is not a solid connection because it does not join previously cuttable stones.

Comments on Definition 2

Definition 2's criterion "joins previously cuttable stones" tries to express solid connection as a move with good purpose: previously cuttable stones cuttable stones are joined so that then they cannot be cut. However, Exa. 2.1 shows that the intention is not fulfilled; such a bad move is allowed under the definition.

Non-definition 3

Some Sensei's Library users frustrated by weak definitions and their effect of allowed bad move examples have suggested "Definition XY must be interpreted by context of usage and / or examples."

Comment: An ambiguous context guideline is not a definition but a non-definition, i.e. the failure to provide any definition.

Definition 4

Definition in Joseki Volume 1 Fundamentals

A solid connection is a string connection that is a thick cut protection, connects exactly two strings not in atari and then blocks opposing stones.

This definition by RobertJasiek occurs in the book Joseki Volume 1 Fundamentals.

Terms Used in the Definition

Thick cut protection is defined as follows:

"A thick cut protection connects a player's stones while making thick shape and protecting against an opposing cut."

Thick shape is defined as follows:

"A play (or stone) creates thick shape if it leaves behind little or no aji. The opponent cannot capture, cut or play painful forcing moves against it."

Criteria in the Definition

Applying the terms, solid connection has these criteria (double or implied criteria are omitted):

• string connection
• makes thick shape
  • the opponent cannot capture the created string
  • leaves behind little or no aji in the created shape
• protects against a previously possible opposing cut
• connects exactly two strings
• previously none of the strings was in atari

Examples of Definition 4

Exa. 4.3  

Counter-examples for Definition 4

Counter-exa. 4.4  

This is not a solid connection because it does not protect against a previously possible opposing cut.

Counter-exa. 4.5  

This is not a solid connection, e.g., because it does not create thick shape.

Counter-exa. 4.6  

This is not a solid connection, e.g., because the opponent can capture the created string.

Counter-exa. 4.7  

This is not a solid connection, e.g., because the opponent can capture the created string.

Counter-exa. 4.8  

This is not a solid connection, e.g., because a previous string was in atari.

Counter-exa. 4.9  

This is not a solid connection because it connects four instead of two strings.

Such is excluded because overconcentrated moves are bad and do not conform to the idea that solid connections are locally good moves.

Borderline Examples of Definition 4

Counter-exa. 4.9  

This is not a solid connection because it connects three instead of two strings.

It is a good move and that is reason why it should be a solid connection. It leaves the left white stone in bad shape and that inefficiency of shape is reason why it should be a solid connection. The definition's condition "connects exactly two strings" might be too strict.

Exa. 4.10  

This is a solid connection.

Counter-exa. 4.11  

According to definition 4, this is not a solid connection because a string was in atari and because three instead of two strings are connected. It is an "escape from atari" and a "thick string connection" though, i.e., a string connection that creates thick shape. That, in contrast to Exa. 4.10, this Counter-exa. 4.11 is not also a solid connection shows the limits of definition 4. The criteria "connects exactly two strings" and "previously none of the strings was in atari" might be too strict in the general case.

Comments on Definition 4

Definition 4 avoids all the bad move examples; they are not solid connections. Its criteria "connects exactly two strings" and "previously none of the strings was in atari" are too strict though and better dropped or replaced. This leaves the following core of definition 4:

A solid connection is a string connection, makes thick shape and protects against an opposing cut.

Makes thick shape implies these aspects: the opponent cannot capture the created string; leaves behind little or no aji in the created shape. The referred to opposing cut is a previously possible one.

Definition 5: cut protection

A solid connection protects against an opposing cut.

This is often accompanied by the string connection criterion. Such a definition of solid connection is seen in some rough lists of go term definitions in literature or the web or supported by a few users here.

Examples for Definition 5

Exa. 5.1  

This bad move example is a solid connection.

Exa. 5.2  

This good move example is a solid connection.

Exa. 5.3  

This bad move example is a solid connection: it string-connects and protects against an opposing cut. The definition does not care that that cut would be bad.

Exa. 5.4  

As before.

Counter-examples for Definition 5

Counter-exa. 5.5  

This is a counter-example because before there was no cut for the opponent.

Counter-exa. 5.6  

Rather then preventing an opposing cut, what is being prevented is a capture by the opponent. Therefore this is not a solid connection according to definition 5.

Counter-exa. 5.7A continued  

If White moves first, then (probably) White cannot cut. Therefore Black 1 does not protect against an opposing cut. So it is not a solid connection.

If connection / cut is understood in a more general form, then a white 2-cut (cut by 2 successive plays before Black starts to defend) is possible and in this sense Black 1 would be a solid connection.

Comments on Definition 5

The definition allows both bad move examples and good move examples. Some counter-examples should be but are not allowed. This lets the definition appear too weak in its assessment of solid connection. The make thick shape criterion is missing while the "protects against an opposing cut" condition is shown as too strict, unless "cut" is understood in a generalized n-cut meaning.

Definition 6: Common Usage in Literature and among Players

According to RobertJasiek's observation, the common usage in literature and among players not having learned their terminology from Sensei's Library is close to a hybrid between Definitions 4 and 5. A careful definition of that cannot be found yet. According to John Fairbairn, Japanese usage sees these types as solid connection: kadotsugi (angle-point connection), katatsugi (solid connection), gatchiritsugi (tight connection) and boutsugi (pole connection).

Conclusion for Definitions

There are these two major meanings for solid connection:

• A solid connection is a string connection.
• A solid connection is a string connection, makes thick shape and protects against an opposing cut created after 1 or 2 successive plays.

The first meaning is scarce outside Sensei's Library; examples see under Definition 1. For the second meaning, examples are studied below:

Examples

Dia. 6A  

The opponent White could cut by 2 successive plays. This fulfils the cut condition of the definition. So we have a solid connection here.

Counter-examples

Counter-exa. 7  

This is not a solid connection because it does not protect against a previously possible opposing cut.

Counter-exa. 8  

This is not a solid connection because it does not create thick shape.

Counter-exa. 9  

This is not a solid connection, e.g., because the opponent can capture the created string and therefore it is not thick shape.

Counter-exa. 10  

As before.

Counter-exa. 11  

This is not a solid connection because the opponent threatens a capture but does not threaten a cut.

Counter-exa. 12  

This is not a solid connection because the opponent does not threaten a cut.

Conclusion on Examples

The definition works as desired: Bad moves are excluded, good moves are recognized, counter-examples work well.