My "Trapezoid" Opening Theory

[PandaHuggles]

Below is a game I played as First Player (White) against an AI from https://temhelk.itch.io/yinsh

I get my butt kicked by this AI if I max out its thinking time, so I only gave it a 1-second thinking time. I also know that another player on here was also able to beat the AI (with 1 second thinking time), but not regularly.

In my experience, this AI is an "Edge Player". It concentrates it rings along the edge of the board.



Personally, I am a "Center" player.

Most of the time, my rings will be clustered at the center to form a "trapezoid" where the longer edge of the trapezoid (3 rings) will be along the centerline.

There are a few other characteristics to my opening:

• Longest Line of the Board - From the "Trapezoid" opening, I generally play along the "longest line" of the board which is just outside of the centerline. The idea is that this gives me a lot of space to form a line. The other advantage to this line over the centerline is that once your ring reaches the end of the board, that becomes the "starting position" for edge play. It would reach the spot where an Edge Player would have ordinarily played during ring placement. So in the game above, it was hypothetically possible for me to form my second line along the edge instead of the centerline. It allows me to pivot more easily.

• "Wall" Defense - The long-edge of my "trapezoid" functions like a wall to helps shield the line I am forming. The "wall" also serves another defensive purpose which is that whenever someone tries to flip my marker, the "wall" might be able to undo the damage, immediately flipping back.

• Line Orientation - Against an "Edge" Player, I usually avoid having my line parallel to their line. Defensively, this often requires them to spend 2-turns to navigate their ring to sabotage me. Offensively, rings of my line is aimed right at their line.

• Speed - I think Center is a tradeoff between speed and defense. I tend to form a line faster than an edge-player, but it is vulnerable to being sabotaged. However, it is often the case that my opponent abandons their own line formation to sabotage me.

• Easy Next Plan- Generally, once I scored my first ring, my remaining rings are often still lined up and ready to start forming their second line. Very often, my opponent is just about to finish their first line, and I am already starting to form my second line.

Against the AI (when made stronger), I would often notice than it evaluates its own win rate to be lower than me at the start of the game; it could go from like 50% to maybe as low as 35%. And then I would mess up mid-game, and it destroys me. And it's always sudden too. It could go from like 35% win rate to suddenly 80% win rate because of 1 bad move on my part.

The downside to this "Trapezoid" opening (which a certain player does to annoy me) is when they are the First player and places a ring at the center just to mess with me.

[YaiHar]

Very interesting! Thanks for sharing.

[Whoopsidoodle]

Thanks for sharing! I guess I'm about to see a live demo of this strategy

[orangeblood]

Wow, thanks for this! In my limited experience, the strongest players use the center opening. However, it does seem easy to mess with even if the opponent doesn't have the opening move... by just playing next to one of the rings. Have you found a good way to react to that?

[PandaHuggles]

I get told the opposite. I was told the strongest players play the Edge, and that I am the weirdo here.

As for people trying to mess with the opening, many have tried.

But it's not so easy.

Here's an example of a recent game I had where my opponent allocated 2 of their rings while the remaining three is focused on the edge.

At a certain point, my opponent can (and did) flip my marker.

But the Trapezoid formation has a very good "anti-flipping" quality due to its ring placement.



I could flip back immediately, but instead, I moved a ring to block the opponent from flipping again, and there's nothing they can do to stop me from undoing the damage they did. It was the cleanest way to just get 5 in a row.

So despite being the 2nd Player (Black), I was the first to score, and my opponent (despite being first) still needs 2 more moves to score their first ring. From the perspective of racing to 3 rings, I am 2-3 "markers" ahead. Note that the marker my opponent left behind when trying to sabotage me... suddenly becomes a potential resource to form my next 5-in-a-row.

It could be argued that flipping me wasn't enough worth it in this case. Had my opponent just conservatively scored their row on the edge, they would only be 1 "marker" behind.

I often just ignore when my opponent flip my marker because I very often have an "undo" option where my rings are just positioned to undo the damage.

In the game of Go, there's a concept called the Ladder.

YINSH sort of has its own version of a Ladder where the opponent could sabotage my line of markers my zigzagging my markers to flip it one by one.... and I can have a ring that zigzags in the opposite direction, just undoing their attempt to sabotage me.

[KivasFajo]

I get told the opposite. I was told the strongest players play the Edge, and that I am the weirdo here.

I'm playing YINSH with the "Olympic rings"-opening (that's my name for it ) since 2003/2004 and won the YINSH Tournament 2005 in Cannes and the YINSH World Championship Tournament 2008 in Prague with it (see https://gipf.com/ for details).

So, I'm one of the other "weirdo's" that are currently leading the YINSH ranking here on BGA.

Michael Reitz

[PandaHuggles]

Ooo!

KivasFajo, in your time playing YINSH in those days, what kind of openings did elite level players like to do? Was mostly edge? Mostly center?

Someone on BGA was also from those old days, and I was told elite level players tend to play the edge.

But... I also read a BoardGameGeek thread where someone argued the edge is for beginners.

So I have no idea.

[KivasFajo]

Yes, online play happened at Brettspieltwelt these days and playing on the edge was most popular.
I found it boring and therefore started to play from the center, because it created more dynamic games.

Michael

[voormaligvleeseter]

I get told the opposite. I was told the strongest players play the Edge, and that I am the weirdo here.

I'm playing YINSH with the "Olympic rings"-opening (that's my name for it ) since 2003/2004 and won the YINSH Tournament 2005 in Cannes and the YINSH World Championship Tournament 2008 in Prague with it (see https://gipf.com/ for details).

So, I'm one of the other "weirdo's" that are currently leading the YINSH ranking here on BGA.

Michael Reitz

Hi Michael, good old times! Reminds me of a piece I wrote (and can't locate anymore) on the same strategy. It gives me more headaches, but it is more fun . Recall that Bramblyspam (or a nick along these lines) also played this way and was extremely hard to beat.

[KivasFajo]

I get told the opposite. I was told the strongest players play the Edge, and that I am the weirdo here.

I'm playing YINSH with the "Olympic rings"-opening (that's my name for it ) since 2003/2004 and won the YINSH Tournament 2005 in Cannes and the YINSH World Championship Tournament 2008 in Prague with it (see https://gipf.com/ for details).

So, I'm one of the other "weirdo's" that are currently leading the YINSH ranking here on BGA.

Michael Reitz

Hi Michael, good old times! Reminds me of a piece I wrote (and can't locate anymore) on the same strategy. It gives me more headaches, but it is more fun . Recall that Bramblyspam (or a nick along these lines) also played this way and was extremely hard to beat.

"It gives me more headaches, but it is more fun ." fits perfectly !!!
And yes, Bramblyspam was one of the best players on Brettspielwelt.de at that time.

Michael