I'd like to introduce some tactics for breaking Mino Castle.
Here, ▲B*44 is threatening to play ▲S*71 on the next move.
As soon as a bishop or silver is placed on 71, the king will be in danger.
When the point 53 has been opened up, the move securing the bishop's diagonal is effective.
In case the point 53 has not been opened, ▲B*34 is a good attack here. Attacking the gold on 52 is one of the ways for breaking Mino. When cutting the bishop with ▲Bx52+, the gold on 61 is pulled out automatically, and then ▲S*71 becomes possible.
If the gold run to 62 against ▲B*34, dangling a pawn with ▲P*52 would be a subsequent attack. gote cannot take it. After cutting the bishop, there is ▲S*71 as well. But, leaving it as it is, ▲P51+ will be a severe move.
In this position, ▲P43+ is the move which pulls the gold out forcibly. In reply to △Gx, ▲L*63 is a good sequence. If taken with silver, sente can gain the gold with ▲Rx61+. And if the gold run to 71, a king-gold fork would occur with ▲L62+, △Gx, ▲S*71.
When attacking pieces are not enough, aiming to make a promoted pawn (Tokin in Japanese) is the theory. ▲P*43 or ▲P*44 is a good move here. If gote has a pawn, the defense with
△P*42 would be available against ▲P*44.
The king in Mino Castle is often aimed by bishop's line. Here, ▲N*74 hits the vital point.
In case of △K71, there is a checkmate with ▲G*82. And in case of △K92, the edge attack begins with ▲P95. To avoid this threat, gote defends with △P64, ▲Bx, △G63 in advance. This line is the typical defense for gote when attacked by the bishop diagonally.
Going with ▲P95 is the first step of the edge attack. The lance on 91 is pulled up with △Px, ▲P*93, △Lx, ▲P*94, △Lx, and then with ▲N*86, it's possible to take the lance. If sente has a silver in hand, ▲S*85 would be also possible when △Lx94.
In case of Mino Castle without G52, sente tries to drop a bishop or silver in hand on 71 as the previous diagram. By ▲G*62, △Gx, ▲S*71, the aim is accomplished.
When sente plays ▲P*62 here, the gold has to move sideways to 71.
And ▲B*53 is a tactical move aiming for ▲R*71+, △Kx, ▲P61+, △K82 (△Kx, ▲G*62), ▲B71+ in the next. If gote has a gold, it would be possible to protect with △G*52. When ▲R*71+, △Kx, ▲P61+, △Kx, sente cannot give a checkmate with ▲G*62 because △G*52 controls 62.
After it proceeds with ▲P*62, △G71, it looks like it's difficult to attack.
However, ▲P95 is a good subsequent attack. Continuing with △Px, ▲P*92, △Lx, ▲S*91, △Kx, ▲R71+, sente succeeds in breaking the castle. Making room for dropping the silver is the essence of this tactic.