: ( 58bb)
Black stabilises his formation in the left centre.

:
White captures the nakade.

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

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

White should simply refrain to play this move so early in the game.
If she ever insisted on this wedge, she should play it much later, after the settlement of Black's upper left corner.

(Referenced by 58ar; 58dc; 58dr)

: ( 108 58bz)
KataGo likes to play the hasami-tsuke in the lower left corner as a kikashi.

Here, however, the exchange for is the game-deciding mistake - in conjunction with the also unnecessary wedge in the left centre before.

After White's earlier atari at Black's nakade, Black can no longer benefit overall from answering White's crosscut of in the upper left corner with the outside atari of , but has to retreat with playing the atari from the inside. Please note that White has not yet connected her two stones in the lower left here.
If White had done without this hasami-tsuke exchange in the lower left corner, Black could no longer benefit overall from defending his lower left corner with or after the sequence in the upper left corner has come to its first temporary stop.

White must simply refrain from playing this move, if she had already played the wedge in the left centre before.

:
The Main Semeai continues.

:
KataGo seems to like White's peep at the upper edge, which does not do any harm.

:
Black must connect.

:
KataGo sometimes plays this White kikashi in the bamboo joint.

However, White cannot gain any local advantage by this exchange.
Quite the contrary, White is in danger of losing one point in the Semeai Variation unnecessarily in the case Black captures her single stone in the right centre with . If Black had sufficient Main Semeai Liberties to spend to connect at and , he would turn the point of into an additional approach-move liberty.

If White let this exchange unplayed, her wedge at usually would be sente, forcing Black to connect at , so avoiding the effect describes above.
Therefore, this move can be considered to be a technical mistake. It is simply superfluous.

Please note that - in the subvariations below - we usually refrained from letting Black benefit by White's mistake.

:
White has to return to the upper right corner.

:
White plays the crosscut in the upper left corner.

:
White has not yet connected her two stones in the lower left. Therefore, it is correct for Black to choose the inside atari.

: (A 58cj)
Black secures his potential territory in the lower left corner, instead of blocking with in the upper left corner.

Please note that this choice (a correct continuation below provided) will benefit White by four points in the Semeai Variation, while not affecting the overall result of the game.

:
KataGo likes playing this push into Black's upper left corner as a kikashi.

Here, however, White cannot gain any local advantage by this exchange. And seen globally, White provides Black with an additional Main Semeai Liberty unnecessarily.
Therefore, this move can be considered to be a technical mistake. It is simply superfluous.

:
White starts the reduction of Black's upper left corner.

:
White connects her single stone at the top, also giving atari at Black's two stones.

:
Black gives atari at White's two stones in the lower right in return.

:
White captures Black's two stones at the top.

: (149 58ck)
Black must recapture.

He would be one point worse overall, if he mistakenly captured White's two stones in the lower left, instead.

: ( 149 58cm)
This push into Black's lower left corner was my second candidate for a potential mistake in this subvariation.
However, after a closer inspection of the alternative continuation the status of this move changed to "false positive".
This exchange in the lower left corner is simply superfluous, and should not be played.

White would benefit by one point in the Semeai Varation, if she connected her two stones in atari, instead.

: ( 149 58cn)
Black blocks immediately.

He would gain one point in the Semeai Variation, compared to the correct line of play below, if he captured White's two stones in the lower left, instead.

: ( 149 58cq)
White connects her single stone in the upper right.

This move was my first candidate for a potential mistake in this subvariation, as White usually benefits in the Capture Variation by connecting her two stones in the lower left.
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".

Connecting her two stones in the lower left, instead, would benefit White by one point in the Semeai Variation, while not affecting the overall result of the game.

:
White plays KataGo's bad-shape move in the left centre.

:
Black answers with the solid connection.

Black plays 3/3 reductions.

Capture Variation:

Compared to the superordinate variation, ...

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

In total, gains and losses compensate for each other.

White + 1 => White + 1

Semeai Variation:

Compared to the superordinate variation, ...

• White's cumulated gain in the upper left corner and at the top is three points.
• Black did not capture one White stone in the left centre, so losing two points.
• Black captured one White stone less in the lower left, so losing two points.
• Black captured one White stone more in the lower left corner, so gaining one point.
• White got an additional point of territory in the upper right corner.
• White captured one Black stone more in the lower right, so gaining two points.

In total, White gained seven points.

Black + 7 => Jigo