Fetlar Hnefatafl

Tafl rules
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Hagbard
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Re: About the draw concept

Post by Hagbard » Mon Nov 26, 2012 6:47 pm

arne64 wrote:Hello, what do you think of this idea: White can get only a draw if at least 3 black pieces are killed. So in order to draw white has to do some kind of strong attack.
This could be another way to avoid the Monstrous Draw Fort, simple and effective. I think it might even be enough to require one black piece killed.

arne64
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Re: About the draw concept

Post by arne64 » Mon Nov 26, 2012 7:17 pm

I think the problem with one black piece killed is that this can happen very early. So back can't do any sacrifices at the beginning playing a weaker player. Also this rule would legitimate draw forts at the beginning if possible. Now they are possible but not really legitimate or accepted.

crust
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Re: Fetlar Hnefatafl

Post by crust » Tue Nov 27, 2012 1:37 am

arne64 wrote:Hello, what do you think of this idea:
White can get only a draw if at least 3 black pieces are killed.
So in order to draw white has to do some kind of strong attack.
That's a good idea - it means no draws in the opening game, but still allows the possibility of any kind of draw fort in the mid- or end-game. Very simple and elegant! I think this rule would rescue the Fetlar version from the draw problem. A very good refinement! :D

arne64
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Re: About the draw concept

Post by arne64 » Tue Nov 27, 2012 9:53 pm

Thank you! I think this would be great for all versions of Hnefatafl. I just had the problem in a tournament game of Scand. museums Hnefatafl where the white player drew before a single piece got killed. Also because in cand. museums Hnefatafl black is stronger it would be effective just to draw all games with white and win the ones as black to get maximum points. I think this should be avoided too!

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Re: Fetlar Hnefatafl

Post by Hagbard » Sat Dec 01, 2012 9:01 am

crust wrote:I think this rule would rescue the Fetlar version from the draw problem.
arne64 wrote:I think this would be great for all versions of Hnefatafl. I just had the problem in a tournament game of Scand. museums Hnefatafl where the white player drew before a single piece got killed.
Adam wrote:I can see one problem. How would this fit in with the board repetition rule? Forbidding board repetition removes draw forts unless they are specified in the rules (as in Copenhagen). In order to avoid perpetual check threats one would need to create a rule that allows draw forts, but forbids other forms of perpetual move draw positions. Tricky perhaps?
The problem with a draw is the early center fort. And in the extreme, the Monstrous Draw Fort.

Currently these variants forbid repetitions:
Copenhagen Hnefatafl
Berserk Hnefatafl
Sea Battle Tafl

Moreover the attackers in Berserk Hnefatafl can break draw forts using the commanders.
The 9x9 board is too small for building a center fort.

Left are these variants, which are exposed to misuse of the center fort draw. The variants are identical with respect to doubtful center forts (like the Monstrous Draw Fort), which are built the same way in all of them:
Hnefatafl 11x11
Fetlar Hnefatafl 11x11
Scand. museums Hnefatafl edge 11x11
Scand. museums Hnefatafl 11x11
Unst unarmed king tafl 11x11
Unst unarmed king tafl edge 11x11


The past two years 1800 tafl games were played on this site. Counting the draws in the exposed variants gives 42 draws:
24 center forts
5 edge forts
1 corner fort
9 perpetual checks
2 cases of too few pieces left on both sides
1 case of white not able to move

With 0 black pieces killed:
3 normal draws and 9 doubtful draws.

With 1 black pieces killed:
3 normal draws and 4 doubtful draws.

With 2 black pieces killed:
5 normal draws and 1 doubtful draw.

With 3 black pieces killed:
9 normal draws and 0 doubtful draws.

More than 3 black pieces killed:
8 normal draws and 0 doubtful draws.

It looks like a suitable threshold to abandon draws with 0 or 1 black pieces killed and to allow draws with 2 or more black pieces killed?

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Re: To draw of not to draw...where is the option?

Post by Hagbard » Fri Mar 08, 2013 3:00 pm

skallatorc wrote:

I am in the situation where a draw is inevitable but the option for draw has not shown up. Anyone know how or when that will be avail?

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Re: To draw of not to draw...where is the option?

Post by Hagbard » Fri Mar 08, 2013 3:22 pm

skallatorc wrote:I am in the situation where a draw is inevitable but the option for draw has not shown up. Anyone know how or when that will be avail?
That's because all black pieces are still on the board. In a discussion some time ago it was decided that white is allowed to obtain a draw only when at least two black pieces are killed; generally for all variants. So while the position is indeed a fine Two Towers draw position, alas white lost because two black pieces were not killed.

Update, NB: Two blacks killed before a draw is not general anymore, but now only required for Fetlar.

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Re: Fetlar Hnefatafl

Post by Hagbard » Sun Jun 10, 2018 1:24 pm

In the Fetlar game, as outlined by the Fetlar Hnefatafl Panel, it is always possible for white to create a center draw fort in his first two moves, and nothing can stop it.

This imperfection of the Fetlar rules of course spoils the game, and something had to be done to prevent white from doing that. As a fix we chose to introduce, that white must capture two black pieces, before allowed to get a draw. This delays white so much, that if white after that still gets a draw, it is more well earned.

There is however another, simple way to solve this rules imperfection. For all other variants we have the rule:
"If the attackers surround the king and ALL remaining defenders, then they win, as they have prevented the king from escaping."
This rule makes the draw-in-two-moves impossible and is first found (to my knowledge) at David Brown 1980 (hat tip Damian Walker). Not being aware of that, the same rule was reinvented here 2012.

The capture-two-blacks rule is an emergency fix for Fetlar only, whereas the surround-all rule comes naturally to the tafl game for all tafl variants.

So I propose that the capture-two-blacks exception for Fetlar be replaced by the general surround-all rule.

Xerxes
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Re: Fetlar Hnefatafl

Post by Xerxes » Mon Jun 11, 2018 10:37 am

Makes sense to me, and brings consistency too.

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Re: Fetlar Hnefatafl

Post by Hagbard » Mon Jun 18, 2018 10:53 pm

Hagbard wrote:
Sun Jun 10, 2018 1:24 pm
So I propose that the capture-two-blacks exception for Fetlar be replaced by the general surround-all rule.
Xerxes wrote: Makes sense to me, and brings consistency too.
Implemented.

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