A news article about the first Early Cretaceous avialan from Japan is available at the following link:
https://www.smithsonianmag.com/science-nature/newly-discovered-fossil-bird-fills-gap-between-dinosaurs-and-modern-fliers-180973551/
Fukuipteryx is the first Early Cretaceous non-ornithothoracine avialan to be described from an Asian locality outside China or Mongolia. Since Fukuipteryx has a pygostyle and is recovered as basal to Jeholornis, it is unclear whether some non-pygostylian birds had a pygostyle.
Link for original description of Fukuipteryx:
https://www.nature.com/articles/s42003-019-0639-4