I know where to find the tablebases but "win in 63" doesn't tell me if and when a capture happens, and in a 2 bishops versus knight endgame the knight tends to get captured towards the end, but how to know whether there's a way to prolong this 51 moves? (knowing that longest distance to mate and longest distance to capture may be other routes)

edit: another example is 2 knights versus pawn (some may think that stuff never happens but I already analysed this twice in my correspondence games), it can take more than 50 moves to win so how to know if there is a way for the defending side not to make a pawn move for at least 51 moves?

is there a way to look up in the tablebases whether a position is winning taking into account the 50-move rule?
I was thinking specifically about 2 bishops versus knight

Vass wrote on 06/01/12 at 12:26:49:

Sure I've been thinking about that possibility. However I doubt that it is really worth to insert the 5-men tablebases if you anyway check manually the 6-men tablebases once 6 pieces are left on the board (like I do). True, the engine will check 5-men tablebases even if there are still much more pieces on the board but what is the real value of that? Normally a transition from 6 to 5 pieces is taking a lot of moves unless it is a simple endgame to understand. If it indeed takes a lot of moves then the popping up of the 5-men tablebasehits in the sidevariations of the ongoing engineanalysis have no real value as the critical 5-men tablebasehits are only popping up behind the horizon.

Anyway this is a very specialized domain of computing which would need severe testing to know the exact optimal configuration. Any volunteers for doing such indepth testing? Probably not so we probably best stick to the methods we trust the most.

Alias wrote on 06/01/12 at 08:23:44:

1) You don't need to buy the Nalimov tablebases to store them on your PC. You can download all of them for free on http://kirill-kryukov.com/chess/tablebases-online/

2) There are quite some pros and cons (also partly explained on the above link) to store the tablebases on your own computer.
Big advantage: 
- While an engine is calculating, it automatically checks if an analysed position hits a tablebase. This can lead to thousands of automatic tablebasehits in an analysis of a specific endgame. This way you have 100% certainty that the millions of positions an engine is calculating, are automatically checked if a tablebasehit is made. So normally leading to higher quality of analysis which is in correspondence chess especially important.

Big disadvantages: 
- You need to store a gigantic amount of data on your pc which can cause some nasty sideeffects.
- I have the impression that the engine seriously slows down by checking the tablebases as it has to continuously swap between memory and disk. So it often takes much more time to go to the same level of depth for an engine.
- If you are quite far from the 6 piececonfigurations, the tablebasehits are quite meaningless as the mainline is cleary something else. Again leading to unusefull consumption of processingpower and time.

My conclusion today is that storing the tablebases aren't necessarily bringing higher quality analysis if time is restricted. For OTB analysis I accept fully the loss of quality in the transition phase to the nalimovdatabases. I am however not sure if I would accept this for correspondencechess as it is often exactly in that phase that the men are separated from the boys.

brabo: I haven't bought the Nalimov tablebases. Just knowing that I can find particular positions on the on-line versions is fine for me.

I tried to google translate your blog. It was quite difficult to follow. I haven't played any CC games in a few years but in my own experience the way to use computers hasn't changed so much even though the programs and hardware have changed dramatically. Someone more experienced, like eg Larry Kaufman, probably has a more modern view on using programs than mine.

Thanks for that Brabo. 
IM or not IM, short or tall, rich or poor. Some websites you know, some you don't.
Didn't know that, top site, cheers muchly.