Sakamoto’s duo with Alva Noto became one of his most profound dialogues in the 21st century, spanning decades and striking a delicate balance between the two and their soundworlds. The Latin roots of the title of their fifth album, Summvs, makes such intentions clear (“summa” and “versus” mean “sum” and “towards”). There’s a bit more of a pulse to Noto’s laptop, while Sakamoto’s piano has a bit more linear development. It builds towards a bit of a surprise, a cover of “By This River,” written by another famous collaboration, between Brian Eno and Cluster in the 1970s. Placed here it gives a most welcome feeling of warmth, like a thaw after a long winter.