Fighting Empty Triangle / Solution

fighting emty triangle - white's next move?  

tderz: [10] from a Korean book, p.229 (ISBN 89-333-0346-4)
All black moves look completely natural, don't they?
Still he voluntarily created an empty triangle.
Should he have exchanged a for b first?

It's not so easy to decide on white's next move, hence the empty triangle can't be that bad and rather renamed fighting empty triangle.

Black's intention - "natural" moves won't do  

tderz: [20] This is Black's intention & desire.

another tesuji  

tderz: [30] from a Korean book, p.230 (ISBN 89-333-0346-4)
+ seem like a fair punishment and the black can be qualified as hamete
(though I cannot read the Korean text).

Still, this is a very interesting idea for a try out in an informal game.

Charles This is Yu Ch'ang-hyeok (W) 6d - Yi Seong-chae, 2d. 26th Myeongin, Semi-final, 1995-05-16. There is a ko in the corner, as I hope everyone can see!

tderz: Pros ... hmm, then it won't be hamete !
Rather it must be strong or wrong !

ko aji  

tderz: [40] Charles, I guess, this ko aji is meant?
=

at present, it does not work  

tderz: [50] It's only aji, because at present, it does not work, e.g. ....

ladder  

tderz: [60] Black won't connect at m or give atari at a, rather simply capture in a ladder -.

indirect protection of cutting point?  

tderz: [70] Could this ko aji indicate an indirect protection of cutting point a?
This nice reinforcing move is unfortunately not sente, threatening the ko aji
(unfavourable two-step ko for White?).

Still, this could be more honte than a huge descend at b (because cut a is still unprotected).
(I did not have had a look at the game)

On the other hand, seeing , Black would feel immediately inclined to hane at b and White is at a loss (she cannot block at c, because Black would capture with d+e).
Neither can White exchange first m for n (- in ^[40]) because Black resists as in ^[50] & ^[60].

Hence, I see a ko, but not a way how it would work in practice. (should replay the game)

simple straightforward?  

tderz: is this very amateurish?
At least it feels big-strong in gote. (But it was Black's sente in ^[30] anyway, so she can't even get this result)

Charles This type of ko appears on p.116 of Teach Yourself Go - so you should all know it by now. It was fought out in the game quite soon. So, I think the book's compiler was lazy; it's not a great place to finish a 'solution', rather the kick-off for a complex fight.

tderz I don't own the book Teach Yourself Go and do you refer to (ISBN 89-333-0346-4)' author with lazy?
Perhaps the 3 diagrams on pages 229-230 are meant as example for something (thickness?, strange moves, tesuji?) from real games.

Charles could you please provide the following moves, as I cannot find the game on GoBase. http://gobase.org/information/games/

Charles Gogod have the game, and I might post some. I'm saying the book is hack work. I don't think anyone who knows the go literature will find that surprising; much of the problem material isn't of a high standard. (Of course I except my own books. In fact my co-author Kim said a book should get written in a month, which tells you what you need to know about the effort usually put in. Buy Teach Yourself Go. Buy Gogod. Actually support the people who try to raise standards!)

tderz: Actually I own several GoGod versions, but did not look there now (I am at work). Actually I liked the book as a practice because it shows many Josekis and asks simply for the next move, then gives two diagrams, one correct (always on top), one wrong. Of course I thought several times "Yes, but what if I'd play here" or more assertive "I can play also here!".
Perhaps I'll buy also Teach Yourself Go.
Charles, I supported the (Go-)book industry of several countries already! My number of unread (Go-)books is growing as their percentage to books in total! This is quite telling.