I thought it would be nice to have a thread to share neat problems that come up in real games (either your own games or games you are studying). Feel free to add your own!
I especially like problems that are not very hard once posed as a problem, but could easily be missed in a fast game.
F1 Then if G2 then H1
This was originally on the side, but I moved it to the corner where the bottom side don’t matter, and simplified the outside positions.
black to plays and keep some of the inside black stones alive
and I made a demo board for it
Nice and tricky, took me a minute!
A5 B5 C5 A3 B6?
Solution attempt
A5 B5 C5 A3 B6?
White has further sente move wB3 to force black to respond. And black in turn can force bA2 with wB2, and then play bA5 to live, or don’t play bA2 wB2 exchange to retain one more possible ko threat.
Another interesting is if black start with bC5, how white is actually going to kill the black group, it would actually involve semeai, making white group outside eye(s), and repeat capture and recapture.
G1 lives as well though, doesn’t it?
G1 also claims the F1 point, so that would seem to be the better solution.
From the The all-in-one democratic game. [The game] - #960 by stone_defender
I found an interesting ko related variations. but with a twist
Black to play and save all black stone without ko.
If bG1, then wE1 and black is dead 
The magic of bF1 is that it prevents wE1 and wG2 simultaneously.
Argh, forgot about the damezumari!
This just looks impossible 
Ya, I was thinking that too… come to think of it, if black is forced to play ko, It is a very heavy ko, like 35 in value?
Yeah of course dying would be pretty bad, but at least black has some local ko threats, and would gain a bit by winning the ko, getting out along the top (so it’s not completely one-sided).
I’ve still got nothing, you’re 100% sure that it’s not ko? 
Must be a a real blindspot for me, I’ve been reading the same ko variation over and over, can’t find anything else that’s even close to working…
Every move coming from the inside can be in some way blocked, Don’t see there are moves from the outside (yet), the outside white wall, looks very solid beside the ko.
I officially give up, do you want to share the solution?
I think I created a problem that cannot be solved (under the context that every stone or even just a part of it can live without involving a ko if the opponent won’t relent).
I defeated myself 
(I will be glad if someone can prove me wrong)
I think this is the point of no return where it has to involved a ko after this where it’s white’s turn to play
I think it is a fun one to point out even with such a strong shape to start with, it is still possible with a result that it could still has potential to be a disaster if you put your mind to it to be play the worst move possible.
I’ll call it a point of no return tsumego
A problem arose from my games today.
White’s turn to play
I am certain I saw tsumego problems similar to this before…
Still white to play, and just one stone switch place, but the result is quite different. (the magic of monkey jump!!)
From a game I played just now:
White just filled a dame. Does black need a protective move inside?
SGF with game continuation removed
Yes
Can you give a variation how you would follow up if black tenukis?
I do it in the sgf ok
