A atmospheric work by the Swedish composer, evoking the shadowy depths of a sea cave. Its distinctiveness lies in its modal colorings and the use of the lower registers of the piano to create a haunting, cavernous resonance.
Pedaling must be precisely managed to support the atmospheric resonance without blurring the harmonic changes.
Comparable difficulty and character — good candidates for what to learn next.
Blå grottan (Op.43) is rated Henle level 4 of 9 — intermediate repertoire, roughly ABRSM grades 5–6. In the RCM system it corresponds to about level 6.
You should be comfortable at Henle level 4 — meaning you can already play level 3–4 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of Blå grottan (Op.43) lasts about 4 minutes.
Blå grottan (Op.43) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.
Pieces at a comparable difficulty and character include Berceuse by Laura Netzel, Berceuse by Laura Netzel, Ballad by Laura Netzel — see the full similar-pieces list on this page.