(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
GN[ ]PW[Chris Oliver]PB[ ]C[This article, aimed at double-digit kyu players, looks at a standard sequence
for invading a corner. It introduces the main lines learners should know rather
than all the possible tricks opponents may try to confuse them.
The 4-4 point is the most-used opening move in modern Go. Surprisingly for
many beginners, the 4-4 point alone doesn’t guarantee territory in the corner. A
common additional move to secure the corner is the 4-3 point; the 3-3 point is
less common. Conversely, the 3-3 point can be used to make territory inside an
opponent’s 4-4 stone:]FG[259:]PM[2]
;B[dd]
(;AW[cc][cd][be]AB[dc][ce]LB[cc:1][dc:2][cd:3][be:5][ce:4]C[DIAGRAM 1

White invades Black’s corner with 1. Black’s next move at 2 (or 3) chooses the side on which
to build a wall – often a critical decision. 3 strengthens; jumping could result in White’s stones
being cut and killed.

The proverb says ‘At the end of two stones, hane’, and here, the hane at 4 puts pressure on White
and reduces the amount of territory White gains by continuing her wall along the side.]PL[B]
(;B[cf]
;AW[cb][db][bf]AB[eb][fc][cg]LB[cb:11][db:9][eb:10][fc:12][kc:A][jd:B][kd:C][bf:7][cf:6][cg:8][cj:D]TR[de]C[DIAGRAM 2

6 prevents White escaping on the left side or cutting at the triangle point.
7 gives White more space to make eyes. 8 prevents the white hane and
means that each further white move along the edge makes only one point
of territory.

9 threatens to escape into the space behind Black’s wall, 10 closes the gap, 
11 and 12 defend against significant cuts.

The sequence normally ends here with White having sente, alive in the corner
but completely enclosed. Black has a very strong wall, which works well in
conjunction with black stones at A, B or C, but less well with stones around D;
this is the main factor determining on which side Black chooses to play 2.
The right time to play (or prevent) this sequence can be difficult to judge and
depends greatly on the outside situation. The territorial value of the sequence
is around 20 points, making it significantly more valuable than most small
captures or monkey jumps. However, the influence of Black’s wall on the
outside can often be worth more than White’s gains in the corner, so other
approaches such as the 6-3, 6-4, 7-3 and 7-4 points should be considered,
especially if the board is relatively empty.]
;W[jj]
(;AE[cb][db][eb][fc][cg][jj]AW[cf][bg]AB[bd][de][bf]LB[bd:10][de:8][bf:6][cf:7][bg:9]C[DIAGRAM 5

Alternatively, Black can cut with 10 to take the corner in gote instead of taking sente.]PL[W]
;W[af]
;AW[cb][db]AB[bb][eb][bc]LB[bb:14][cb:13][db:15][eb:16][bc:12][af:11]C[DIAGRAM 6

In this variation, after 12, White should play on the left side (or top).
If White makes the mistake of trying to save the corner with 13, the sequence to 16 shows
how Black can chase down White’s group.]
;B[fc]
;AE[bb][cb][bc][fc][bd][af][cf][bg]AW[ec]AB[bf]LB[db:7][eb:8][ec:9][de:10][bf:6]C[DIAGRAM 7

Diagram 7: White plays this 7 if escaping to the top is better. 10 is necessary to prevent a double
atari and so 8 can be captured, but Black has a good result.])
(;AE[cb][db][eb][fc][cg][jj]AW[cf][bg]AB[bd][de][bf]LB[bc:12][bd:10][de:8][af:11][bf:6][cf:7][bg:9]C[DIAGRAM 3a]))
(;B[bf]
;W[cf]
;B[de]
;W[bg]
;B[df]
;W[af]C[DIAGRAM 4

Diagram 4 shows another sequence for Black
to take sente.]))
(;W[cc]
;B[dc]
;W[cd]
;B[cf]
;W[bf]C[DIAGRAM 3

There are several variations to the sequence above. For example, to take sente, Black can play 4 as in
Diagram 3. White follows with 5 as shown and Black can then play elsewhere (‘tenuki’).]))
