Music involves many choices. With improvised music, I have sometimes found it an intriguing exercise to listen and consider the amount of choices that are occurring. Whether to dwell on a theme that has emerged or move on. Whether to embrace the current mood or deviate.

Testament is the latest in Keith Jarrett’s long series of CDs of live piano improvisations, drawn from concerts last year in Paris and London. Improvisation becomes more complex if a group of musicians needs to agree, and if they are making their choices in front of an audience. By working alone, Jarrett has avoided the first of those issues, but by shunning the studio for most of the last twenty years he has chosen to take on the second one.

The first cut, from Paris, is one of several on this set that finds Jarrett exploring a desolate musical landscape. At the end, he comes to a repeated B. You can hear him picking various chords to harmonize the B, evidently trying to determine which one can conclude the piece, which mood he would like to be the final one. The final note is a calm one, but the peace is hard-won.

The first cut on the third disc, from London, is another one that creates a lot of tension. It paces in G with dissonant, blues-flavored chords over a stern bass pattern. One listens, wondering if it will break through to different terrain, but it doesn’t. It could go on for a long time, but after eight minutes Jarrett chooses to conclude and move on.

Jarrett changed the format of his solo concerts with a series of shows in 2002 (the first of which became what may be my desert-island pick out of his discs, Radiance), but since then they have followed a similar program. He is now playing a series of brief pieces, usually including a pensive ballad, a rowdy avant garde piece and, occasionally, an affirmative gospel tune. If one piece sets a mood, the next one often disrupts it. In this respect his choices don’t vary a lot, but there are still an immense number of choices within those boundaries.

However, in Testament he has made another choice: to include liner notes which give very personal background to the music. His wife left him not long before these shows, and he is candid about how that influenced his mood. That casts an intriguing light on some pieces, such as the tense one from London I described. However, it also makes one think about the ballads, some of which are heavy on sentiment. One can hear Jarrett deciding how much sentiment to include. I am still debating whether he included too much.

That said, the liner notes conclude with a simple sentence from a writer friend of Jarrett’s: “How fragile and serendipitous things are indeed, unbearably so.” There is one four-note passage in the first track from London, around six minutes into the piece, which conveys everything in that sentence. Jarrett doesn’t dwell on it, though. Another choice worth considering.

The act of making this amount of choices in front of an audience is daring. And the resulting music is one that will take years to give up its secrets. I suspect I may make different choices in years to come about how to respond to it.