Life In 19x19

Some more international participation from Iyama: he just won in the round of 16 of Samsung cup, beating Li Xuanhao (a rising Chinese pro you might not have heard of but he's top 30 in world now). Tomorrow he plays in the quarterfinals, will be a tough game, against Xie Erhao (who just knocked out Park Junghwan).

I was surprised Li never moved out with the n15 cutting stone (I've seen that in other games and gives black some future problems, Elf thought he should at various times, p13 at p14 seems more common recently and then black doesn't feel need to add n13 to prevent o13) so when Iyama captured that I liked his position. Interestingly Elf identified s6 as a point white should have invaded the right side moyo that just became a territory without the lower left getting in too much trouble.

Thanks mace for quickly adding to go4go!

Uberdude wrote:Some more international participation from Iyama: he just won in the round of 16 of Samsung cup, beating Li Xuanhao (a rising Chinese pro you might not have heard of but he's top 30 in world now). Tomorrow he plays in the quarterfinals, will be a tough game, against Xie Erhao (who just knocked out Park Junghwan).

I've been following Iyama's performance at Samsung cup, and I must say that he lucked into an easy path. His opponents were relatively weak compared to what Korean and Chinese pros had to face. Anyway, Iyama's luck has just run out; he's been eliminated.

4th Miejin game is on, here's the first day's play. Some complex fighting which ended up with Cho U getting a load of territory and Iyama a wall. I had a quick look with Elf and LZ 181 but with these kind of fighting with ladders involved I don't trust them too much without doing a lot of exploration and validation. Anyway, after the dust settled both AIs think it's essentially even (Elf slightly more leaning to white but the bots have 7.5 komi).

Wow, this is an even position?!

Funny, because I preferred black. I guess the left side has a lot of potential for white.

Iyama won: the centre potential ended up too much. When Cho jumped at o9 Iyama poked the shape at q8 and Cho never connected with q9 (I suppose he thought it submissive and didn't like white sabaki with q4 next) and Iyama ended up cutting off o9 whilst Cho solified the right side and corner territory but Elf says o9 was too big. Cho's reduction/invasion of the left side ended up living in combination with the h13 cut but Iyama got more than enough in the centre.

5th Meijin game is in progress today: opening showed the influence of Elf with lots of ignoring approach to 4-4 to approach another 4-4.

Update: lots of big trades in the late middlegame meant Cho U won by 9.5 to stay in the match with Iyama 3 wins, Cho 2.

Uberdude wrote:lots of big trades in the late middlegame meant Cho U won by 9.5 to stay in the match with Iyama 3 wins, Cho 2.

It was quite strange to follow live using LeelaZero: before Cho U connected his upper and lower groups, LZ seemed confident that an attack on them will result in Iyama's win. However Iyama chose to play away, let Cho U play some moves in a row in the center to connect his groups.

I wonder if Iyama misjudged the position (he thought he would win by playing peacefully), or is it that LZ miscalculated something in the fight in the center (for the attacking variations that it had "in mind").

sorin wrote:I wonder if Iyama misjudged the position (he thought he would win by playing peacefully), or is it that LZ miscalculated something in the fight in the center (for the attacking variations that it had "in mind").

9.5 seems to imply a huge miscalculation, for that far along in the game.

hyperpape wrote:

sorin wrote:I wonder if Iyama misjudged the position (he thought he would win by playing peacefully), or is it that LZ miscalculated something in the fight in the center (for the attacking variations that it had "in mind").

9.5 seems to imply a huge miscalculation, for that far along in the game.

Compared to that peaceful position where Iyama allowed Cho to sort-of connect through the middle the following changed by the time they got to counting:
- Iyama's bottom ~60 point group died (so Cho's big bottom group didn't)
- Cho's top ~35 point group died (so Iyama's top left didn't)
- Cho's right ~15 point group died, rescuing Iyama's 4 stones, leading to
- Cho's top right ~15 point corner died

I was impressed Cho found 202 as a clever response to Iyama's clever 201 allowing him to engineer the favourable trades.

Iyama's busy: today he beat Yamashita Keigo in the first Tengen title match. It was a big fighting game as often between these two, and Yamashita was doing pretty well but at the end Yamashita tried to capture some of Iyama's stones which had a ko to escape (and profit), but Iyama cleverly made some ko threats which meant Yamashita's threat against a big dragon of Iyama's that had been the target of his attack for much of the game weren't a clean threat to kill so Iyama ignored and had just enough aji to wriggle out (via another ko that was too heavy for Yamashita to fight).

Cho U won another kadoban to level the Meijin title match at 3-3, decider is on 1st/2nd November. Elf says black was winning or even throughout, well done Cho U! White 126 as tesuji cut/probe at p15 was perhaps Iyama's last chance.

I knew Cho was playing well, but I really did not expect this.

Iyama plays Ichiriki Ryo in the first game of this year's Tengen Oza title match today. Can Ichiriki break his 10 game losing streak in title matches vs Iyama? (whitewash in previous Kisei, Tengen, Oza)

Update: Ichiriki turned it around in the middlegame to win by 2.5! I added a few variations from Elf at the critical moments.

Uberdude wrote:Iyama plays Ichiriki Ryo in the first game of this year's Tengen title match today.

Wow, so Iyama is now defending three titles simultaneously with the Meijin, Tengen and Oza going on at the same time. But he's meeting Ichiriki in the Oza, I'm pretty sure. Yamashita is challenging him in the Tengen.