This is the second in a series of short, modern works focused on timbre. It is distinguished by its economy of notes and careful consideration of the piano's resonant qualities.
At Henle 4 this is an intermediate piece that expects secure technique and real attention to phrasing. The main demands: chord voicing — bringing out one note inside a handful of others; fine finger independence within the hand; and precise articulation — the difference between crisp and blurred is the piece.
Focus on the subtle differences in voicing between the primary melody and the accompaniment.
Comparable difficulty and character — good candidates for what to learn next.
A level or two down with the same spirit — ideal if this piece is still out of reach.
Where this piece's skills lead: slightly harder works making similar technical demands.
Lesser-known works by the same hand, at a comparable level.
Citrus Color No.2 (Op.84) 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 Citrus Color No.2 (Op.84) lasts about 2 minutes.
Citrus Color No.2 (Op.84) 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 Blue Waking by Michio Aramaki, Citrus Color No.1 by Michio Aramaki, Citrus Color No.3 by Michio Aramaki — see the full similar-pieces list on this page.