A subterranean fantasy wonder! A hidden Japanese castle built inside a massive underground Lush Cave or Amethyst Geode cavern.

Massive cherry trees grow under glowing Amethyst Cluster light and Glowing Berries hanging from the cavern ceiling. A subterranean river moat illuminated by Sea Lanterns surrounds the castle walls. The color palette pairs deepslate stone, amethyst purple, cherry blossom pink, and glowing aqua blue.

+-------------------------------------------------------------+
|              UNDERGROUND CAVERN SAKURA CASTLE               |
|                                                             |
|           ( GIANT CAVERN CEILING WITH GLOW BERRIES )        |
|      =================================================      |
|     /                                                 \     |
|    |    +-----------------------------------------+    |    |
|    |    | SUBTERRANEAN SAKURA KEEP (Deepslate/Quartz)| |    |
|    |    +-----------------------------------------+    |    |
|    |   ~ ~ ~ [ ILLUMINATED UNDERGROUND RIVER MOAT ] ~ ~ ~ | |
|  ~~+~~~+~~~~~~~~+~~~+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~+~~   |
+-------------------------------------------------------------+

Step-by-Step Building Guide

  1. Excavate Mega Cavern: Carve or locate a large subterranean cavern (at least 30 blocks tall).
  2. Build Cavern Base: Construct a deepslate stone castle base on an island in the cave center.
  3. Build Quartz Keep: Build a 2-tier white quartz keep that contrasts against the dark cave walls.
  4. Illuminate Ceilings: Hang Glow Berries, Shroomlights, and Amethyst Blocks along the cavern ceiling.
  5. Build Underground Moat: Fill the cave floor around the castle with water lit by underwater Sea Lanterns.