Disclaimer: I am not sure this subject hasn't been touched before and I'm not even sure it isn't nonsense.
In real life ladders prefer a vertical position. Not so in go where they tend to have a diagonal direction.
In go we know the ladder as a sequence of moves in which alternating an attacker threatens to capture and a defender threatens to escape. Typically this repeats in a fixed pattern until an edge is reached or a so called ladderbreaker. This is the global aspect of ladders. Its success might be decided far, far away. If possible a local solution is preferable.
Usually we only consider diagonal ladders; they resemble a staircase. The ladder than develops parallel to a diagonal of the board.
I propose also to consider vertical ladders of which the next diagram is the simplest ( boring ) example.
first edit: please skip the hidden part it is rightly dismantled by Li Kao.
$$c dia 1: B to kill
$$ . . . . . . |
$$ . . . . . O |
$$ . . . . X O |
$$ . . . . X O |
$$ . . , . X O |
$$ . X X X O O |
$$ . X O O X X |
$$ . . . . X . |
$$ ------------+
- Click Here To Show Diagram Code
[go]$$c dia 1: B to kill
$$ . . . . . . |
$$ . . . . . O |
$$ . . . . X O |
$$ . . . . X O |
$$ . . , . X O |
$$ . X X X O O |
$$ . X O O X X |
$$ . . . . X . |
$$ ------------+[/go]
To kill B has to climb the ladder, chasing W up until W breaks his neck against the ceiling.
Like the diagonal ladder also the vertical ladder has more exiting variants.
Here an example resulting from a trick play in the tsuke-hiki joseki after a tenuki.
$$c dia 2a 6 tenuki
$$ --------------------+
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . 8 4 3 5 . . . |
$$ , . 0 9 7 2 , 1 . . |
$$ . . . . . . . . . . |
- Click Here To Show Diagram Code
[go]$$c dia 2a 6 tenuki
$$ --------------------+
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . 8 4 3 5 . . . |
$$ , . 0 9 7 2 , 1 . . |
$$ . . . . . . . . . . |[/go]
$$c dia 2b trickplay 5 at a
$$ --------------------------+
$$ . . . . . . 0 . . . . . . |
$$ . . . . 9 2 a 6 . . . . . |
$$ . . 8 c 3 1 O O X X . . . |
$$ . . . , 4 O X X O , X . . |
$$ . . . . . . . b 7 . . . . |
$$ . . . . . . . . . . . . . |
- Click Here To Show Diagram Code
[go]$$c dia 2b trickplay 5 at a
$$ --------------------------+
$$ . . . . . . 0 . . . . . . |
$$ . . . . 9 2 a 6 . . . . . |
$$ . . 8 c 3 1 O O X X . . . |
$$ . . . , 4 O X X O , X . . |
$$ . . . . . . . b 7 . . . . |
$$ . . . . . . . . . . . . . |[/go]
after 4 B fears both the ( diagonal ) ladder at b and the capture at c ( miai ) so he tries the trickplay 5 at a.
7 defeats the diagonal ladder; 8 defeats the trickplay by a vertical ladder as shown in the next diagrams.
$$c dia 2c
$$ ----------------------------+
$$ . . . 6 3 5 . O . . . . . . |
$$ . . 1 X 2 X O . O . . . . . |
$$ . . . O 4 X X O O X X . . . |
$$ . . . . O O O X X O , X . . |
$$ . . . . . . . . . X . . . . |
$$ . . . . . . . . . . . . . . |
- Click Here To Show Diagram Code
[go]$$c dia 2c
$$ ----------------------------+
$$ . . . 6 3 5 . O . . . . . . |
$$ . . 1 X 2 X O . O . . . . . |
$$ . . . O 4 X X O O X X . . . |
$$ . . . . O O O X X O , X . . |
$$ . . . . . . . . . X . . . . |
$$ . . . . . . . . . . . . . . |[/go]
The ladder gets its base.
$$c dia 2d B gets killed in the opposite corner
$$ +---------------------------------------+
$$ | . . . . . 8 5 1 . X X . O . . . . . . |
$$ | . . . . 7 3 4 X X O X O . O . . . . . |
$$ | . . . . . 6 2 . O O X X O O X X . . . |
$$ | . . . , . . . . . O O O X X O , X . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
- Click Here To Show Diagram Code
[go]$$c dia 2d B gets killed in the opposite corner
$$ +---------------------------------------+
$$ | . . . . . 8 5 1 . X X . O . . . . . . |
$$ | . . . . 7 3 4 X X O X O . O . . . . . |
$$ | . . . . . 6 2 . O O X X O O X X . . . |
$$ | . . . , . . . . . O O O X X O , X . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]
$$c dia 2e 8 at a
$$ +---------------------------------------+
$$ | . 9 a 5 1 . X X . X X . O . . . . . . |
$$ | . 7 3 4 X X O X X O X O . O . . . . . |
$$ | . 0 6 2 . O O . O O X X O O X X . . . |
$$ | . . . , . . . . . O O O X X O , X . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
- Click Here To Show Diagram Code
[go]$$c dia 2e 8 at a
$$ +---------------------------------------+
$$ | . 9 a 5 1 . X X . X X . O . . . . . . |
$$ | . 7 3 4 X X O X X O X O . O . . . . . |
$$ | . 0 6 2 . O O . O O X X O O X X . . . |
$$ | . . . , . . . . . O O O X X O , X . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]
Question1: Is this last vertical ladder the only way to kill B's top or is there a local solution?
Question2: Anyone another type of a vertical ladder other than the two types shown here?
first edit: hidden the example critized in the next post by Li Kao ( thx )
I think I am so I think I am.
. I'll repair this example ( shouldn't be too difficult ). What about my other example. Isn't it cute?
