If you have been following recent pro games, you probably noticed that some basic josekis you learned from book are hardly ever played. One of those is the inside hane that occurs in the popular one-space low pincer.
The first variation I learned as a kyu player was the hane at A in this shape. We rarely see it anymore except in special circumstances. That is because people’s understanding of joseki is evolving and some moves are discarded in favour of other variations, such as the extension at B, or hane at C before extending at B.
(There are other exotic variation such as the trickplays at D or E, or jumping up at F, etc.)
Regarding A, this sequence is practically inevitable (unless Black wants to try weird trickplays). We will analyse and destroy the outcome of 3 basic josekis by applying tewari:)
I.) I’m sure most of you have seen or even played this joseki before. In the end Black spends one more move than White and ends in gote with an impeccable shape.
Formerly regarded as favourable for Black, it turns out Black becomes overconcentrated (in gote).
We will compare it with this familiar shape. This is considered slightly better for Black, but nonetheless provides excellent material for the sake of comparison.
By moving the triangled stone from the marked position, we get the simplified starting shape in our joseki. Note that this step is a minus for Black.
In the next step, we put back the removed stones.
White exchanges 1 and 3, certainly a loss, but Black then throws in the ridiculous stone at 5. Though judging both sides’ losses is difficult, we can also say that the position before 5 is very similar to the starting position two diagrammes up, and Black 5 makes this good for White.
II.) The downstairs atari at 1 is another option for Black. Once Black descends at 3, White will inevitably get a wall to extend to the side.
(Note that White pushes one more time at 8. I believe that older joseki books omit this push.
However, I have multiple modern sources that take it for granted, and apparently, Black has no choice but to extend at 9:p It’s certainly a good exchange for White: By giving Black two more points, White stretches the wall and gets an extra liberty that dulls Black’s next turn.)
To analyse this shape, we don’t need to move stones around. A simple comparison with another joseki, shown on the right, suffices to conclude that Black gets swindled on the left.
By comparing the territories, we count 17 points for Black on the left and 15 on the right. The difference in White’s influence, however, by far exceeds 2 points. I think the conclusion is very clear.
Remember that you can use the familiar joseki on the right to compare it with various corner results. (Ideally, both players spent the same amount of moves in that corner.)
III.) The last basic variation occurs when Black ignores the atari at 2 and trades ponnukis with White. I knew before seeing the tewari analysis that White is locally favourable. While both ponnukis have comparable influence to the outside, White has more points in the corner.
But the tewari is so amazing:)
By removing the marked exchange, we get two innocent, uncorrupted ponnukis.
(My source remarks that White gains slightly in that exchange by having the outside stone.)
Then we put back the stones that used to be inside the ponnukis. The position of Black’s stone is considered better than that of White’s stone. That means, getting the better stone captured is again a loss for Black.
As absurd as it looks, this tewari is just a rearrangement of moves. You can see that comparing shapes is not difficult, but sometimes tewari demands imagination and creativity. In this case the tewari was done with stones that were already off the board.
Source: These analyses and more sequences (not shown here) can be found on WeiqiTV.