Minecraft Dungeons II's Sift as a new dimension in Minecraft Java. Play the Singer's melody at an ancient city portal to get there.
The Sift from Minecraft Dungeons II, rebuilt as a new dimension in Minecraft: Java Edition 26.3. You only need Minecraft: Java Edition; Dungeons II is where the content comes from, not something you need to own.
Find an ancient city. Near the big deep dark portal frame at its center, place 8 note blocks and play the Singer's melody: B flat, D sharp, G, G sharp, D, C sharp, E, A. Right-clicking a fresh note block 4, 9, 1, 2, 8, 7, 10 and 3 times tunes them to those notes, in order. Each correct note lights part of the frame; after the eighth, the frame opens onto the Singer's Portal in the Sift. The same portal takes you back.
Outside the Sift and that portal, the game plays exactly like normal Minecraft. Singleplayer.