Anaguma.

How it goes together

The lance steps up from 1i to 1h and the king takes its corner. The silver closes the hole on 2h, one gold stands on 3h and the other on 3i, and the knight never leaves 2i. Nothing can give check to a king in the corner without first breaking through three generals and a lance.

What it is good against

Nothing is stronger. A king that cannot be checked lets you attack with everything else, and a common Anaguma plan is simply to trade pieces until the opponent’s thinner castle gives way. Many top-level games are decided by who gets to build one.

Where it breaks

It is slow, it gives up the corner as an escape (the king has nowhere left to run once the wall goes), and while it is being built the pieces that will form it are not doing anything else. An opponent who attacks early, before the hole is sealed, is the Anaguma player’s worry.

When to build it

When you expect a long game and the opponent is not attacking yet. In the ranging rook form shown here the rook has gone left; static rook players build the mirror image on the other side.