A few moves from the end of game 727636, I suddenly noticed that I had a potential unstoppable run at the final rank. Unfortunately I only noticed this after my opponent had already started his unstoppable run too.

Can someone who actually knows what they're doing please have a quick look and tell me if there was a point at which I had a possible win, or whether I had a possible defence?

Many thanks.

with a quick look, you seems to be in a loosing position from move 49 or even before. at move 57 your opponent can play F8E7 to stop your attack instead of continuing his attack. maybe 49 C5B6, more offensive, is winning, but i don't feel so, and to be sure i need more than a quick look :)

OK, I'm glad to hear that I was doomed, as I don't feel so bad about throwing it away. I was wondering why I put a piece on d6 - I think that may have wasted 2 moves. But my vision - my ability to imagine the board after conjectured moves, is next to nothing alas (I have so many finger prints on my monitor from trying to “remember” breakthrough/dvonn/amazons moves!) so I get lost very easily when hypothesising. Maybe I should ask for a draughts board for my birthday…)

Doomed form 49?

What about 61.c5-c6 - and win in 2!

Argh! That's the move. I've been confused by the rank7/8 pairs before. As you can see, I just hold off. However. you're right, once the front one is moved - taking a sacrificial piece, say, then the other one is absolutely defenceless from right in front. I honestly thought that I'd need an extra piece to attack his _two_ pairs, which is why I wasted time back on rank 4. That's why you're a 1900+ in ch.1, and I'm not! Efchariso, yper'! I'm so glad I asked now, hopefully I can learn from this.

brunbrun was right though. Your opponent made a mistake in the 60th move, he could have played 58.f8-e7 (or 60.f8-e7) and prevent this attack.

Yes, but instead of 57.c5-d6?, 57.b4-a5 is winning with the threat b6-a7 b8xa7 a5-b6.
If 58. d8-c7 you exchange and play a5-b6, and if 58.c8-c7 a5-a6 for instance is winning.

That does look like the most direct win.

But perhaps 57. c5-d6 is OK anyway. With a lot of help from Wanderer I see that black 58. f6-e5 was a mistake. White plays 59. d6-d7 followed by b4-a5 with an easy breakthrough on the left. (58. f8-e7 would lead to the same result.)

Wanderer thinks the best defense to 57. c5-d6 is 58. d5-d4 (trying to win the race, I assume) but simply 59. b1-b2 makes Wanderer very happy, though he can't actually see the win.

Wanderer is right.
After 59.b1-b2 White wins with the d6-d7 tactical shot if needed.

Amusingly, 57.c5-c6 is also winning. There is a little trap, though.
If Black responds 58.d8-c7,
59.b4-a5 loses to 60.c7xb6
59.b4-c5 loses to 60.b7xc6
But 59.c6xb7 wins: 60.c8xb7 61.b4-c5 62.c7xb6 63.c5-d6!

[game;id:727636;move:56;title:the position we are talking about]