East of the Sun is the first album in a history dating back to 1967 that Amsterdam’s brilliant ICP Orchestra has made without its co-founding pianist and composer Misha Mengelberg, who was forced to retire from music due to progressive dementia. Mengelberg was the heart-and-soul of the ensemble; he can’t be replaced. Yet at the same time, the group has always experienced personnel change and taken advantage of new members and shifting dynamics. Sitting at the piano bench on East Of The Sun is Guus Janssen, an admirer of Mengelberg but a musician with his own voice, both as an improviser and a composer—he wrote the wildly careening “Rondo,” an intensely shape-shifting jaunt that swings jubilantly between circus-like chaos and storming early jazz swing. Mengelberg’s long-time musical partner Han Bennink chose the repertoire for the album, including a number of themes by his old pal such as the brief opening hymn-like chant called “Psalm,” the previously unrecorded “Oorwurm” (Dutch for earwig), a martial ditty that lives up to its title, and “Der Jofelen Pels Slip.” But he also brings in pieces by some of the other excellent composers in the group including Ab Baars, Tristan Honsinger (showing off his typical whimsy on “Bolly Wolly,” which teeters on the edge of insanity) and Michael Moore, as well as fellow travelers like Maurice Horsthius and the late Sean Bergin, who wrote the Italianate swinger “Lavoro,” which plows straight into an ebullient version of “Moten Swing.” The album concludes with a raucous reading of the standard that gives the album its name. There may not be any new tactics or tacks on display on East Of The Sun, but the fact that ICP seems to be weathering the loss of its leader in such elegant, electric fashion is more than we need.