hi guys,

I wonder what would be the estimated required strength to beat a relative ok pro (something like 7d pro) with 9 stones.
Is it possible for a EGF kyu ?

Cheers,
Otenki

The dan of a pro doesn't tell you so much about how strong they are nowadays (there's lots of weaker old 9ps). If I take your question to mean an active pro who often gets through the first round of international tournaments, then no, I think an EGF kyu is a bit too weak to win on 9 stones in an one-on-one game with moderate time settings. A French kyu on the otherhand...

Well I live in Belgium so I'll just hop over the border then and declare my rank overthere

At the Go Congress in Portland, I played in a simul against a pro ( 5P? 6P? I forget ). The guy next to me was 9K AGA with a stable rating. He took 9 stones and won.
His strategy was very simple: just avoid complications and connect all perimeter stones to tengen. When he did that, one of the pros's groups was short on eye space.

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I wouldn't compare that to a serious game with a pro.

Something pros do in teaching games, and indeed amateurs too, is if the opponent is playing good style, proper moves they won't play anywhere near 100% and will allow themselves to be beaten as a reward; whereas if the opponent is playing bad moves or overplays then they will concentrate more and fight harder to win to punish the naughty opponent.

In other words, if you play good moves, you win. If you play bad moves, you lose. Even against pros.
Very original. I must remember this strategy.

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- Bantari
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otenki, there's another angle: one game is not enough.
Yes, of course, anything can happen -- including 9p self-atari --
so another way to look at your question is
what winning percentage are you talking about? 1% of the time? 30%? 50%? 99%? They're quite different.

For example, at least in China, sometimes when one pro A asks about a new person who's
an existing student (or friend) of another pro B,
A can ask B, "How many stones?" A is asking B what is the person's level relative to B.
If B says, "About 3 stones," B means B can give that person 3 stones handicap
and that's about correct, meaning, 50/50 win rate. So if A knows B's level, then
A has an idea of that person's level, too.

Maybe that's what you were asking? Can an EGF kyu person get 50/50 win rate with a pro at 9 stones?
Or, did you really mean literally "possible," as in, even 0.1% chance of beating a pro at 9 stones?
The two questions are very different.

Bantari, that's not what Uberdude was saying and it's not fair.
What Uberdude said was if a student plays good moves, and the pro knows she can win if she plays
full strength despite the student's good moves, she can choose to pull back
(or, in some other cases, purposely leave weaknesses to see if the student can exploit them, etc.)
to let the student win in a teaching game.

Agreed. The emphasis here should be on "teaching", not on "game".

For players EGF 10k or stronger, H9 winning probability 50% is possible if Black has some reasonable idea how to use his handicap stones. (I beat 6p as a 10k, because I sacrificed consistently to control other big parts. With handicap stones, such a strategy is straightforward. Ok, I also needed to make one really good, triple purpose move, which let the professional "cry" in astonishment.)

However, I have seen many single digit kyus without idea how to use handicap stones, and their winning chances were close to 0%.

Hence, I would not say that it is a matter of exact pro strength, but mainly a matter of having an idea at all what the handicap stones are good for. (Players knowing to use their influence best are already strong dans and can take up to about 130 komi to compensate H9. Kyu players do not have that knowledge yet, but must have at least some basic idea of how to use the handicap: boxes, connect to each other, splitting attack or sacrifice etc.)

Reading: useful in Go, useful on forums too.

The teaching-game aspect is very relevant. I've also seen someone who was a solidly ranked KGS 1d win with 4 stones against a pro in a small teaching game simul. But I think 4 stones for a KGS 1d should usually be nowhere near enough if the pro is actually playing to win. Particularly if the time was decently paced, which was the case, so that if the pro seriously wanted to win, at the very least it would not have been hard for him to deliberately complicate the game and expect tactical mistakes given that there would not be enough thinking time for the weaker player to avoid them all.

Ilya Shikshin can give 7 stones (or possibly even more given his ferocious fighting style) to an EGF 1kyu. Based on these go9dan games, it seems Lee Sedol (who is admittedly stronger than the pros mentioned in the original question) could give him 3 stones. 3 + 7 = 10. Perhaps on reflection I should say I don't think an EGF 1k can't beat a strong pro on 9, but I would bet on the pro. 3k or weaker then they are very unlikely to win. It is around 1k-1d that I think 9h is even.

I agree 100 percent. I would not expect myself to win with 4 stone. Although I feel I can win easy, it is always different when you play and they find a way to win.

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"The more we think we know about
The greater the unknown"
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Man, there is always a spoilsport getting in a way of a good quip...
I know, I know...

So let me rephrase:
If you play good, he plays bad. And vice versa. Happy?

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- Bantari
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WARNING: This post might contain Opinions!!

Still not a good quip. The less clever your quip is, the more emoticons you need to broadcast to your audience that it is meant as playful self-deprecation, not as a contribution to the discussion.

I think indeed I should have phrased my question differently, I meant "In a teaching game".

Thanks for the replies guys allthough I'm still not sure.

You know what, I'll try it out and see how it goes

Cheers,
Otenki

In a teaching simul, sure a 5k can win on 9 stones. Go for it! Remember don't be defensive and think if you get all 4 corners you will win. Keep his stones separated and yours connected so he's always under pressure of attack.

I also support Uberdudes estimate.

The only evidence I personally have is a simultaneous game against a 9p at the EGC last year where I managed a jigo on 6 stones (I'm about 1d egf). A win would also have been possible as I lost a big part of one corner due to a reading mistake in early endgame. I played two more simul games against other pros on 3 and 5 stones where I went for the kill, unsuccessfully though pro magic is incredible...

Based on these experiences I believe I could play on par with top professionals at an 8 or 9 stone handicap in a serious 1-on-1 non-blitz game. Maybe 7 stones with a "weak" professional, if there is such a thing
Additionally substract up to 2 stones in case of teaching games or one of my occasional 2d moods.