Lo-Fi ZEN

Lo-Fi ZEN does not play back finished tracks. The lo-fi jazz is assembled note by note, the rain and the whale song grain by grain, on your phone while you listen. It is an app for falling asleep, for focusing, or simply for passing the night.

■ No loop seam
No song is looped as a whole; everything is put together on the device as it plays. The tape loops have lengths that don't divide evenly into beats, so their overlap keeps drifting, and hours later there is still no "here we go again". That does not mean a brand-new song every time; it means nothing snags your ear, however long you keep it on.

■ Five worlds
- Lo-Fi ZEN — a wooden house at night. A girl listens to lo-fi jazz on vinyl. Twelve songs across the four seasons, from a hazy spring moon to winter under the quilt. The picture follows the song.
- KUJIRA — the sea. Swell, whale song, waves, underwater, the deep, offshore wind, drift ice.
- KUJAKU — a peacock under the stars. Handpan, bronze bells, singing bowl, a distant piano, echoes, solar wind.
- YAKUMO — ancient mountains under layered clouds. Forest morning, campfire, autumn insects, rain, waterfall, mountain stream, thunderclouds, cave drops.
- KAIRO — an endless temple corridor. Into the Mist, Stone Steps, The Long Gallery, Row of Lanterns, Bell Hall, Midday Boards, Rain Under the Eaves, Endless Stairs. Drifting patterns and breathing chords.

Every picture moves: thin layers over a single painting. Rain falls, the bulb flickers, mist drifts, embers rise.

■ One dial for the sea, star and mountain songs
The KUJIRA, KUJAKU and YAKUMO songs each have a single dial. Rainfall for the rain, distance for the whale, scale for the waterfall. Turn it while the sound plays and it leans over on the spot. The Lo-Fi ZEN and KAIRO songs have no dial and simply play.

■ An ending that doesn't startle
Before the time is up the sound sinks slowly, and only its tail is left. You won't be woken by the music cutting out just as you drift off.

■ All 42 songs are free
Every song is free to play, with 10- and 20-minute sessions. Get the one-time "No Ads" purchase (not a subscription) to remove ads and unlock 30 and 60 minutes, "endless", and custom durations.

■ A record of your nights
Sessions are kept on a calendar. The calendar itself stays on your device (anonymous usage events such as play start and end, and crash reports, are sent to help improve the app).

Requires Android 8.0 or later. Japanese, English, Chinese (Simplified and Traditional), Korean, French, German and Spanish (switch in Settings).