: ( 58ap)
White peeps at the upper edge.

:
Black has to connect, of course.

:
White continues with capturing Black's single stone in the lower left.

:
Black's immediate connection is mandatory.

:
White gives atari at Black's nakade.

:
Black gives atari at White's two stones in the lower left in return. It is best for him to play this atari as early as possible,

: ( A 58as)
White connects her two stones, but which is a grave mistake, as long as the upper left corner is not yet played out - as it is here.

White must continue with the crosscut at , instead, either before or after she captured the nakade with .
Black would be forced to answer her crosscut with the inside atari of , whereafter her connection at would become a viable option again.

Only a two move difference makes a game-deciding difference here.

:
Black defends his formation in the left centre, also giving atari at White's stones at the left.

:
White has to capture the nakade.

:
KataGo likes to insert this hasami-tsuke in-between.

However, this move is likely to increase the susceptibility to errors in the following course of the game unnecessarily (and can be a genuine mistake; 58by), and so can be considered to be a technical mistake in the timing of moves.

White should keep this move in reserve, and play the endgame sequence after her hasami-tsuke in the lower left corner in succession - if ever.

:
White also likes to insert White's wedge in the left centre in-between.

However, this is another move that is likely to complicate the course of the game unnecessarily (and is a genuine mistake, if played too early; 58dr), and so should be left unplayed here, as White will be unable to take any advantage of it.

:
Finally, White return to the upper left corner by playing this crosscut.

:
White has already connected her two stones in the lower left with , so Black chooses the outside atari here, punishing White for her earlier mistake.

:
White connects on the inside.

Playing the atari at first would also be possible.

:
Black continues with this hane.

Alternatively, he might consider giving atari at in the corner.

:
White connects her stone in the corner, so creating an approach-move liberty for her left-hand group.

:
Black is able to give atari at White's five stones.

:
White has to connect.

: (134 58at)
White plays the cut in the upper left corner as a kikashi.

This move was the candidate for a potential mistake in this subvariation, as I felt that Black's shape in the upper left corner would be strengthened by this move unnecessarily.
But after a closer inspection of the alternative continuation I had to admit that I was too hasty in the very beginning. The status of this move changed to "false positive".

As it turned out, the exchange for does not have any effect on the further course of the game. Therefore, White could also do without this move.

:
Black has to give atari.

; :
Please note that these forcing moves would be viable threats, too, if the marked exchange in the corner were not on the board.

:
White plays the final atari after her wedge in the left centre.

:
White's push destroys some points of Black's corner territory, without losing any tempo in the Main Semeai.

:
Black simply captures.

: ( 147 58ay)
White plays KataGo's bad-shape move in the left centre.


White would benefit by two points in the Semeai Variation, if she connected her single stone in the right centre, instead.

: (A 58ba)
Black must capture White's single stone in the right centre.

He would lose one point overall, if he played the solid connection at , instead.

:
White plays the central attachment in the left centre, aiming at creating some points of territory there, and also at destroying Black's potential eye above.

:
It is best for Black to descend to the upper edge now.

:
Black takes further profit outside the Main Semeai area.

Black must not play any reduction

Capture Variation:

Compared to the superordinate variation, ...

• White's cumulated gain in the upper left corner is four points.
• White's cumulated gain in the left centre is four points.
• Black's cumulated gain in the lower left corner is five points.
• Black destroyed one point of White's territory at the upper edge.
• Black did not capture White's two stones in the lower left, so losing four points.
• Black captured White's stone in the right centre, so gaining two points.
• Black destroyed one point of White's territory in the right centre.

In total, White gained three points.

Black + 2 => White + 1

Semeai Variation:

Compared to the superordinate variation, ...

• White's cumulated gain in the upper left corner is four points.
• White's cumulated gain in the left centre is four points.
• Black's cumulated gain in the lower left corner is five points.
• Black destroyed one point of White's territory at the upper edge.
• Black captured three White stones more at the left, so gaining six points.
• White captured one Black stone more at the right, so gaining two points.
• Black destroyed one point of White's territory in the upper right corner.

In total, White lost three points.

Black + 2 => Black + 5