White has two other defensive schemes, not involving ... P2d. White can defend the edge by an early ... S3c, rather than the usual S4c, to meet N2e by ... S2d to defend the edge better than in the standard lines. This generally leaves White with little offensive potential, so Black should castle left, still planning the knight attack. Alternatively, White can induce an early bishop exchange. Since the bishop is often a target for Black's attack, this has some appeal, but the downside is that the absence of rook and lance leaves many drop squares for the Black bishop, which must be guarded by White's generals. This is apt to leave him with nothing to do but move aimlessly while Black builds up his position calmly. Black normally sets up the "Incomplete Fortress", an ideal castle when bishops are exchanged early.
1... P3d 2 P7f P4d 3 P1f G3b 4 P1e S4b (4... G3c is occasionally seen, to answer 5 R1h by G2d. Instead of R1h, Black can play as in Variation 2 above, plus castling and P2f, aiming for a timely N2e if the gold stays on 3c or P4e if it retreats.) 5 R1h S3c (5... G5b 6 P1d Px1d 7 Rx1d P*1c 8 Rx3d is a questionable gambit by White) 6 P1d Px1d 7 Rx1d P*1c 8 R1h G5b 9 S3h G54c 10 P2f P3e (10... K6b 11 G6h K7b 12 K6i S6b 13 N1g P5d 14 N2e S2d 15 R2h S5c 16 P*1b S6d 17 P1a+ Bx1a 18 Nx1c=
Side line after 18.Nx1c=
18... Nx1c 19 P2e wins material, and White has no castle.) 11 N1g (Black strikes before White can set up the strong defense ... S3d, ... P2d, and ... N3c.) S3d (11... P2d 12 R2h G3d 13 K6h K6b 14 K7h planning S2g-1f and P2e) 12 N2e K6b 13 G6h K7b 14 K6i (Black castles left in these lines as White has most of his army on the other wing.) P5d 15 K7h S6b 16 Nx1c+
16... Bx1c 17 P*1b B2d 18 P1a+ N3c 19 R1b+ G34b 20 P2e ! and White must lose something.
After 20.P2e !
1... P3d 2 P7f G3b (If White exchanges bishops himself he will simply be one tempo behind this line. If 2... B4d 3 Bx4d Px4d 4 B*4c [or Black can play as in the "Trident" line] N3c 5 Bx3d+ N4e 6 G4h! B*5e 7 L9h B9i+ 8 S7h +Bx9h 9 P4f with advantage.) 3 Bx2b+ (If Black waits, White may close the diagonal by ... P4d at a time when Black cannot transpose back to our main lines.) Sx2b 4 S8h G7b 5 S7g S6b 6 G45h P7d 7 P6f S7c 8 G6g K5b
After 8... K5b
(If White plays ... S3c next, his shape resembles a "trident" or pitchfork, each pair of generals being one prong while the king is the handle.) 9 K6h S6d (9... S8d 10. S8f prevents White from getting a pawn in hand by ... P7e) 10 K7h P9d 11 P5f (Black refrains from answering on the edge, because with White's king in the center, Black has no interest in an edge attack on the ninth file. A Black pawn on 9f might give White more chances to start such an attack.) P9e 12 G66h S3c 13 S4h
(Black's castle is known as the "Incomplete Fortress" and is considered to be a very good choice when bishops have been exchanged. While the normal "Fortress" castle, with the king and second-rank gold shifted one square to the left, is slightly more secure, the "Incomplete" version defends more squares against bishop drops. Strategy for both sides now has great similarities to the bishop exchange lines in even games.) N7c (13... P7e 14 P6e !
Side line after 14.P6e !
14... Sx6e [14... Px7f 15 Sx7f S7c 16 P*7e helps Black] 15 Px7e S5d [else 16 P5e and P*6f] 16 S7f P6d 17 N7g S6c 18 S5g N7c 19 S6f P8d 20 P8f.
Side line after 20.P8f
White can do nothing, while Black can build up by P1f-1e, P5e, R5h, and finally P*6e. Note that Black refrains from advancing P2f so that his rook can move without allowing B*2g.) 14 S8f (stops the intended P7e). P8d 15 S5g P8e 16 S7g
(Black doesn't mind the loss of two moves, as White can no longer play N8e and hence cannot exchange pawns on 7e due to P*7d. This strategy is often seen in even games as well.) P4d 17 P2f P3e (if White just makes passing moves, Black could exchange off his rook's pawn, advance P1f-1e, and answer ... G2b by N1g-2e x1c+) 18 P2e P5d 19 P1f S5c 20 S4f S3d 21 P2d
21... Px2d 22 B*1b, winning the knight.