White plays a 3-4 inside approach, black attaches outside, white hanes underneath
The result appears similar to joseki of the week 11.

Diagram 1.

After white 4, black can also play at a instead of at 5 in diagram 1.
White 6 is preferred instead of a, since when black cuts, the black corner territory is larger than the similar result in joseki of the week 11.

Diagram 1.

After black 3, white can take sente, having a successfully undermined blacks corner territory, but leaving black with a wall facing down the left side.
White cannot cut at a, and black can later jump at b, so the wall is fairly thick.

If there are any questions about the joseki of the week,
or if they are too basic/under-examined/complex, let us know in the comments!

Diagram 1.

White 4 above is forced. White can play either a or b next.

Diagram 2. – - – - – - – - – - – - – - – - – Diagram 3.

White 1 in diagrams 2-3 allows black to cut on either side.
White gains extra thickness from the ponnuki in both cases.
In diagram 2, white continues with 7 at a or b.
In diagram 3, where black aims for outside influence, white can continue with a or tenuki.

diagram 4.

If white plays tenuki at the end of diagram 3, then black can play 1 and 3 in diagram 4.
However even if white plays tenuki a second time, the corner is still a ko at a.

Diagram 5.

white plays 1 above to ensure access to both corner and top side of the board.
Black no longer has the option to choose whether to take the corner, or influence on the top side.
However, white has a lower position than if white played as in diagram 2.

If there are any questions about the joseki of the week,
or if they are too basic/under-examined/complex, let us know in the comments!

White normally plays 4(d13) after black 3(d14), but c(d15), d(c17) or tenuki may be possible. These will not be looked at here however.

In joseki of the week 4, black a(e14) next was looked at. This week black 5 at b(c15) is considered.

Black can either tenuk or play around a(k17) now.

White can either play at a(c17), black b(d17) then white c(b16) to take some of the corner, or d(b15) to gain sente.
Black plays b in response to a, since white can live in the corner otherwise.
Black replies to d(b15) with ac17(), since playing at c(b16) will result in bad shape and bad aji in the corner.

Black can also play this way. Now black has a secure corner and sente, but the white group is solid and has greater influence.

If there are any questions about the joseki of the week,
or if they are too basic/under-examined/complex, let us know in the comments!

After white plays a or b, black usually plays c but d is possible.

When using the sold connection, the joseki continues with
both players making extensions, ending in blacks sente.
White 3 can also be at a(d10).

When using the hanging connection, white can extend one extra space down the side.
However, white needs to be carefull of the weakness at a(c8).
b(b13) is the usual responce to an immediate invasion at a(c8) by black.

If there are any questions about the joseki of the week,
or if they are too basic, let us know in the comments!

White can now play one of a, b or c in the above diagram.
In each case, black will end up with a formidable wall facing the top side.

Black can also play 8(e14) at b13. This leads to white fighting outside.

4 at b14

After this joseki, white can play around a to keep access to the left side, or can take sente.
The black wall is now thick.

If white plays at b in the 1st diagram, this is the simple continuation.
White can jump to a, or take sente.

This is the continuation if white plays at c in the 1st diagram.
White can come under blacks wall with b, but white cannot jump to a now.

If there are any questions about the joseki of the week,
or if they are too basic, let us know in the comments!

White directly contacts with 4(d16) to which black plays an outside hane at 5(e16)

When black plays 1 at c18, white often settles the position with the above sequence.
White can now choose between securing the corner at a(b18), or playing a pincer at b(d9).

Black may play 1 at e18, Giving white the the corner, while black takes sente.

If white can’t make a profitable position on the left,
then preventing black from gaining the corner territory is a possible strategy.
This may occur when stones on the left side are low and black already has, or can easilly reduce any framework white builds.

Black 7(f18) is essential to solidify his influence when there are black stones nearby on the top side.
White is still not completely alive in the corner.
White can play a(d17) directly, poke at b(e16) first and then live with a(d17) to leave a cutting point at c(f15).

If black plans to focus on the top side, then the above can be played.
Black is left with a thick wall and sente, while white retains access to the left side.

Black plays the inside tsuke to the white 4-3 stone, and white replies with the hane under.
Black 5(c16) is the standard reply.
The shape is similar to when black approaches a white 4-3 corner, and white pincers at a(c13).

However in this case, without the white pincer black can happily extend down the left side.

This is the normal continuation.
It gives black a nice base, while white has a solid but low group.
If white plays tenuki instead of 3(f16), black can play a(g16) to press white low and build a wall facing the left side.

White 1 at b18 is a mistake since it becomes easy for black to attack and make
an excellent wall while white crawls.
Later it is sente for black to play a(g18), closing the top side.

Black usually plays this way to build influence towards a moyo on the top.
White has a cut at a which needs attention.
Playing at b above threatens to cut 1 and 3 apart and prevents black from
immediately cutting at a.

This is the most common continuation.
White usually makes an extension to about 3
to gain a good base for the group.
The exact extension depends on the surrounding and can be any of a.
If there is a strong black group nearby on the left, then a shorter extension may be used.
If it was omited, it becomes easy for black to poke around c and attack white.

If the moyo that black is building is further to the right, then black can instead extend to b to enlarge it.
Otherwise when there are already black stones around b, protecting from the cut at 4 is prefered.
After extending, white has a solid group and has gained sente.
Often this joseki is played in situations where white can reduce
blacks moyo easily or otherwise make good use of having sente,
so black has to be carefull that the situation is appropriate when playing this.

When there isn’t enough room for a proper extension, C12 can work well.
White is no longer forced to respond to E13 with D12.

Other variations after black plays D14 are planned to be covered in a later week.

If there are any questions about the joseki of the week,
or if they are too basic/under-examined/complex, let us know in the comments!

White plays a low approach to blacks 4-3 stone and black responds with the high diagonal.

Black can gain a nice shape by extending along the top. White might like to prevent this with a play around a or b, but without support in the upper right of the board, it is easy to end up in trouble.

White needs to look after his stone at c15 to prevent black either playing a pincer or pressing down at a.
If white plays the two space extension, black protects the corner then exends to 4. White 1 is closer than ideal, so black can afford to strenghen white this way.
Instead of playing 2, black can now make the good extension at b. if white doesn’t extend up around c, black can press down on the two space extension and gain a wall facing b.

If white plays the 3 space extension instead, black immediatelly invades rather than protecting the corner first.
After the exchange, both players have thick shapes and white has an open skirt on the corner, however black has gained sente.

If there are any questions about the joseki of the week,
or if they are too basic, let us know in the comments!

The Joseki this week is when black plays for influence along the left side.

Black 3 in the above diagram is necessary instead of a hane to the third line.
If black does hane, white descends to B17, then cuts at E16.

b is an important point for both sides to decide whether white gets sealed into the corner.

If black has a stone on the Top side around c, then he might play 9 in the above diagram at a instead, giving black a strong wall facing the left side.

If there are any questions about the joseki of the week,
or if they are too basic, let us know in the comments!

The diagram shows a 4-3 pincer joseki. Here black plays at 5 instead of the more common a or b.

White would like to connect 2 and 4 from the above diagram, but can’t immediately succeed.

The correct move is for white to play D18 first.
Now if black saves C15, white can trade and capture D16-17,
which is usually a happy result for white.