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Topic: Positional differences between renju, Pente and gomoku
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watsu

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Registered: Dec 16, 2001
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Positional differences between renju, Pente and gomoku
Posted: Dec 19, 2022, 7:24 AM

This position is from a good renju problem posted in the renju.net forum. I don't think the 19x19 board size will make a difference for this position. In renju, black (2nd player) has a win by force. Reasonably tricky; I pushed stones around for about 5 minutes until I solved it. In Pente, black (2nd player) has a very easy win. Not worthy of a puzzle. From what I can tell, based on computer analysis, the position seems to be a draw in gomoku.
K10,K11,K12,L11,M10,J11,H11,L10,M11,L12,L13,M9,J12,L8,L9,K7,J6,K8,M8,N7,O7,J8,G10


Hopefully, I (or others) will find more interesting example positions to add to this thread.

Retired from TB Pente, but still playing live games & exploring variants like D, poof and boat

watsu

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Re: Positional differences between renju, Pente and gomoku
Posted: Dec 22, 2022, 2:19 AM

The position below is a fairly easy renju white (second player - shown as black here) wins problem (problem #8 on this page), but it turns out to be a position in which the first player (white here) eventually has a win in both gomoku and Pente. Unfortunately, the first player doesn't have a win by continual threats (or forces) as is typical for renju problems. It'd be nice to find a position which made a good puzzle (with different solutions) for all three games. However, since all renju first player wins are also gomoku first player wins and all gomoku second player wins are also renju second player wins coming up with a good puzzle for all three games may be tricky and require something like a white overline win in renju and a different win in gomoku or a black win in gomoku which fails in renju.


K10,K9,J9,L9,J11,M9,N8,L10,M11,K11,L12,J12,H13,H12,H11


Retired from TB Pente, but still playing live games & exploring variants like D, poof and boat
watsu

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Re: Positional differences between renju, Pente and gomoku
Posted: Dec 22, 2022, 2:50 AM

The position below is one of the deepest I've seen arise out of a potential continuation of an actual (swap2) Pente game. In renju and gomoku, the first player has an eventual win. But, as a challenge I recommend looking at the Pente position without placing any additional stones on a board (physical or computer) and seeing how well you are able to visualize the next seven stones placed and the eventual outcome of the game from this position (not a VCT) if both sides play optimally. I think it would be a Pente position which most Pente players wouldn't be able to analyze successfully during a timed over the board game.




Retired from TB Pente, but still playing live games & exploring variants like D, poof and boat
watsu

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Re: Positional differences between renju, Pente and gomoku
Posted: Dec 24, 2022, 12:11 AM

This is a swap2 Pente I saw recently, except shifted to the top of the board. Black can win in 8 moves in Pente. In gomoku, the white stones have a win but it takes several more moves than just 8 for white to achieve it against best play by black. On a 15x15 board with the top right corner filled as here (but with opposite colored stones) black (using the white stone positions here) has a positional advantage, but not a clear winning sequence that I found. Note that if all of the stones are shifted down one intersection on the board then black does have a winning sequence in renju. This isn't quite what I was hoping to find in terms of a position which works well as a Pente, renju and gomoku problem, but it's getting closer.



Retired from TB Pente, but still playing live games & exploring variants like D, poof and boat
owen_

Posts: 26
Registered: Dec 1, 2022
Re: Positional differences between renju, Pente and gomoku
Posted: Dec 26, 2022, 2:12 PM

There are numerous books of Renju problems of any difficulty from wins in 1-2 moves and up to problems dedicated only for top players.

There are a lot of gomoku problems, mostly online.

Are there any pente problems available? At least a hundred =)

watsu

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Re: Positional differences between renju, Pente and gomoku
Posted: Dec 26, 2022, 3:18 PM

Yes, possibly I'm chasing a unicorn here. I'm just curious whether there are positions which make good puzzles for all three games at the same time while showing the differences between the games. Also, maybe this is a book about ninuki renju positions, but so far I haven't found a translator for it.

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watsu

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Registered: Dec 16, 2001
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Re: Positional differences between renju, Pente and gomoku
Posted: Dec 28, 2022, 4:44 AM

After 16. F12, white (here) has gomoku and renju wins, but the renju win takes a few more moves, due to rule differences between gomoku and renju. In the (highly unlikely, but possible) event that this position were to arise in a Pente game (there are four different sets of surrounded pairs on the board, which would be highly unusual in Pente) black has a win in eight moves, regardless of white white attempts.



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watsu

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Re: Positional differences between renju, Pente and gomoku
Posted: Dec 30, 2022, 6:40 AM

The position in this game after 13. ... Q8 is an interesting one for gomoku and renju, since it's a first player win in gomoku but a second player win in renju. Unfortunately for this thread, though, in Pente the first player can win in three moves, so not an interesting Pente position.




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watsu

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Registered: Dec 16, 2001
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Re: Positional differences between renju, Pente and gomoku
Posted: Jan 22, 2023, 4:29 AM

Well, if I don't exactly have a unicorn here, it at least resembles a narwhal. Black (player 2) has a win in this position in renju, gomoku and Pente. However, the least number of moves to get to a win given best play by white (player 1) is different for each game, as is the optimal choice (or choices) for white's next move to prolong the game.


K10,L11,L12,J10,K12,K13,J12,H12,N12,N11,N13,M12,M11,L13,K14,K9,O13,P14,H13,G12,H11,G14,F13,G13,G11,F14,J11,F11


Alternately, the F11 stone can be removed and shortest black wins found for each game. ETA: I looked at it again and the F11 stone is needed to differentiate between gomoku and renju in this position, I think.


Message was edited by: watsu at Jan 23, 2023, 2:42 AM


Retired from TB Pente, but still playing live games & exploring variants like D, poof and boat
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