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

In the original problem we should play Bxc6 before Rxh7+ so that if black sacrifices his queen to stop mate we can keep our rook!

Ne7+  Kh8 Bxc6  and if black does not sacrifice his queen then we can play Rxh7+ (or Qxh7+) and transpose to the mating line given by obscurebean. If he does sacrifice his queen then our material advantage will be greater because we have not played Rxh7+ yet.

In the revised problem we can play 1.Ne7+  Kh8 2.Qxh7+ (our rook on h3 is actually a better attacker than our queen on b1 after our next move) Nxh7 3.Be4 and black never gets a chance to sacrifice his queen after f5 4.Rxh7+ and 5.Kg2#  after g6 then 4.Bxg6 fxg6 5.Be5+ Rf6 6.Bxf6#  or 4.Bxg6 Kg7 5.Bxe5+ f6(or Nf6) 6.Rh7#

The revised problem took me a long time to figure out. Is it a coincidence that adding a Bishop to the starting position changed the problem the way it did or did you think of it beforehand but decided the first problem was better for some reason? I don't think I would ever be able to solve this if you did not tell us it was a forced mate in 6. When you said that I decided that for the f4 bishop to matter the e5 to h8 diagonal would need to be opened. Since our king still needs to move in some lines to deliver mate, Be4 instead of Bxc6 made since once I realized it would force g6 and not allow the black queen to be sacrificed to stop mate.

I actually found many ways to win in the revised problem. The hardest part for me was finding why 2.Qxh7+ would lead to a faster win that 2.Rxh7+ (easy win but longer than 6 moves).

Nc1

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.

It was sloppy not intentional. Not sure how I confused Nc1 with Qd1. They both end in 1 at least. Sorry Taras!  

Thanks for noticing my error Timelord2067!

That was the previous move. The current move is move 25. I vote for Nc1. (b3 blunders away at least 2 pawns, by the way, which is why nobody's taking it seriously.)

b3 - 1 vote (Timelord2067)
Nc1 - 6 votes (XMRpromotions, jjacob, languagehasmeaning, boolberry, lottery248, Foxpup)

I am very interested in playing chess.No one can not beat me in chess among my colleagues.Chess also actives the nerves of the brain.So it is the beneficial game for mind also.

25. Nc1

I enjoy in those chess problems...  Thanks

Your move bitcointalk. You have the white pieces

The current position is updated below:

25.Nc1    c4