I introduce the basic tactics for breaking a Yagura Castle.
Looking at Diag.1, experienced players imagine ▲S*41 or ▲S*52 for attack. When ▲S*52, if the gold run to 53, sente can take the opponent's bishop with ▲S*41+ (Diag.2). In general, when trying to break a castle, it's better to attack the gold, not the silver, because the gold is stronger than the silver as a defending piece. It can move six squares, and silver is only five.
As for ▲S*41, it depends on the situation whether it works effectively. In Diag.1, after ▲S*41△G-31, in case of ▲S-52+, the bishop can run to the left, and in case of ▲S-52= (unpromoted), the gold can run to 53. There is no subsequent attack. If sente has a pawn in hand, ▲P*43 would be a severe move to take the bishop, though. ▲S*41 doesn't work well singly. But, by cooperating with other pieces, it works well.
For example, in Diag.3, ▲S*41 becomes a good attack. Continuing with △G-31 ▲S-52= △G-53 ▲S-51= (Diag.4), the attack succeeds. The bishop cannot take the silver due to the rook being on 72. The attack with the rook and the silver is often seen in the endgame of Yagura Strategy.
One more example in real pro games.
It's sente's turn at Diag.5. Although there are no attacking pieces for sente, it's possible to launch an attack with hand pieces, a rook, two silvers, and a knight.
Here, ▲S*41 △G-31 ▲S*52 (Diag.6) is a good tactic for breaking the Yagura. In reply to ▲S*52, if the gold run to 53, sente would keep on attacking with ▲N-43 which aims at the gold on 31. Gote's castle become unsafe immediately.
In this way, if you have a silver in hand in Yagura Strategy, it would be good to consider the way to attack with ▲S*41 and ▲S*52 first.