Signed: Sadanobu (貞信)
Publisher: Asai Kinjirō (Marks 18 - seal 25-367)
Related links: Japan Arts Council - all four panels;
The far left panel has the number 4 on it and the center panel has the number 3. There is no apparent number on the right-hand panel. This numbering system raises more questions than it answers.
We now know what the missing panel looks like. (Follow the link to the Japan Arts Council above.) The play is Yoshitsune and the Thousand Cherry Trees. The missing panel shows Mimasu Gennosuke IV (三枡 源之助) as Yoshitsune (よし経). The artists has been identified as Hasegawa Sadanobu II (1848-1940).