Nice job finding the solution. The reason why this problem can be difficult even for good players is that it requires a move that is common only in the opening or middle game.

The studies referenced below are interesting because just like remembering the ability to castle very late in an endgame, scrambled positions are much harder to memorize than normal chess positions.

http://theinvisiblegorilla.com/blog/2012/02/15/how-experts-recall-chess-positions/

"In de Groot’s most famous demonstration, he showed several players images of chess positions for a few seconds and asked the players to reconstruct the positions from memory.  The experts made relatively few mistakes even though they had seen the position only briefly.  Years later, Chase and Simon replicated de Groot’s finding with another expert (a master-level player) as well as an amateur and a novice.  They also added a critical control: The players viewed both real chess positions and scrambled chess positions (that included pieces in implausible and even impossible locations). The expert excelled with the real positions, but performed no better than the amateur and novice for the scrambled positions (later studies showed that experts can perform slightly better than novices for random positions too if given enough time; Gobet & Simon, 1996).  The expert advantage apparently comes from familiarity with real chess positions, something that allows more efficient encoding or retrieval of the positions."

Yes I am sure. It is hard to provide a clue without giving away the answer.

There are at least two active chess threads on bitcointalk

https://bitcointalk.org/index.php?topic=1148538.0
https://bitcointalk.org/index.php?topic=1190988.0

Your move bitcointalk. You have the white pieces

The current position is updated below:

25.Nc1    c4

This problem was not created by me and is fairly well known.

Black to move. Checkmate in 2



Give everyone some time to think about it. Once you find the answer you will know you are right.

I created the original problem first and only added the bishop on f4 to illustrate the point I was making in responding to ObscureBean. The idea was not difficult for me once I made the original problem. The bishop can prevent the kings escape as you discovered.

I like the first problem better because unlike many chess problems it makes you think about variations that are not forced. It also requires more accurate play because of the material imbalance. As I noted already move order had some importance even after the correct plan was identified.

The second problem is not ideal because the material situation allows white to win with imprecise play.  In the So vs Nakamura problem I chose among two positions in part for the same reason. In one position there were multiple winning moves including 29...Be3 (instead of 29...h3+) which was chosen. In the other position, precision starting with 31...Qxf2 was required to win. In that case I also presented the problem requiring more precision.

In creating a problem I start by imaging some pattern (Ne7 and checkmate on the h file in this case). Then I can add or subtract pieces to make things easier or more difficult. Some think it is fun to checkmate by moving the king which is why I added that possibility here.

The problem was not easy but after seeing the pattern (knight on e7 and checkmate on h file) this type of problem will become easier in the future. Obscurebean saw the correct concept but still needs to think more about the best move order (in case black sacrifices the queen to avoid checkmate).

After you understand the first problem, think about how the revised problem can lead to forced checkmate instead of a material sacrifice by black to prolong the game. How can the new piece (bishop on f4) help assist the white attack in a forcing manner that does not allow black the same defense as in the first puzzle?

Soon I may start posting chess problems on Twitter. My hope is that more chess players will become interested in bitcoin after being exposed to this thread.  So feel free to talk about bitcoin related issues here in addition to chess.

https://twitter.com/ChessBTC/status/652587629163233280

I am glad to hear you are enjoying it.  There are many good sites to play chess online and study tactics. I will try to add some value by making comments about how to think about certain types of positions.  After our game I will be happy to help analyze it and share some of my thoughts.

If anyone likes here chess problems have a look at my thread. I have starting posting problems and will continue doing so. Some will come from real games (or positions that could have occurred in real games). Others I will make up.

https://bitcointalk.org/index.php?topic=1148538.msg12643278#msg12643278

Thank you. I am glad you enjoyed the problem.

Great work on finding the right idea but look closely at your move order for an even better option in case black decides to give up the queen to stop mate. In some chess problems every move is a check leaving few options for the opponent. Things are not always so clear in real games. Adding some uncertainty by giving one side an option to give back material in order to stop mate can be helpful training.

Below I made a slight modification of the chess problem to illustrate my point.  Checkmate can now be forced in 6 moves. Although the mating line is one move longer than the variation you gave in the original problem, there is greater clarity due to no ability of black to stop checkmate.



People who already saw your proposed solution of the original problem can still try to solve this one. The shortest forcing line will look slightly different.

New chess problem. White to move. This one is not from a real game. I just made it up. Have fun!

Your move bitcointalk. You have the white pieces

The current position is updated below:

24.Qd1   Rcd8

For that to work you would need to assume that the stocks you purchase will appreciate faster than the bitcoin you used to purchase them.

Provide me with your life expectancy 20 years down the road and your inflation adjusted spending estimates during retirement plus your forecast for the price of bitcoin at that time. Then I can give you an estimate.


I am curious about one more thing. How do you plan to live comfortably without a yacht?

White was playing with the goal of securing a draw in that game. Sometimes when you work too hard to limit complications you end up making suboptimal moves.  My comment is not meant to imply c4 was a bad move.  I am just referring to the goal of white in that game.

https://github.com/ethereum/wiki/wiki/Morden

New testnet

Is this default behavior Monero specific or does it also apply to the Boolberry simplewallet and GUI?

Good default behavior

Some clues:

1. Black can either force checkmate in three moves or force white to give up massive amounts of material to prevent it.
2. If you want to checkmate your opponent, identify possible escape square(s) for their king. Now figure out how to eliminate those escape square(s).
3. Dxxlxxxxon




Nice work! By now I am sure some of you realize my third clue was deflection (of whites knight from protecting the f4 square). The above solution is very aesthetically pleasing but some of the readers of this thread may still want to think about how black should respond if white plays Qc1 or Qd2 after black plays Qxf2.

Now that ObscureBean has solved the puzzle, I will provide a link to the game where it could have occurred:
http://chess-db.com/public/game.jsp?id=5202213.2016192.178568448.28893


In this position black played Be3 (also winning) instead of 29....h3+ 30.Kxh3 Rf2 31.Bxf2 which would have led to our problem position

Your move bitcointalk. You have the white pieces

The current position is updated below:

23.Nxd7   Rxd7