Raku XIII Seinyu (1887-1944)
楽十三代 惺入

Born as the eldest son of Konyu, Seinyu succeeded as the 13th generation in 1919. Seinyu died of a sudden illness on March 8th, 1944. The posthumous name Seinyu was given to him by the 13th generation head of Omotesenke Mujin Sosa (1901-1979), Sokuchusai.

The name Seinyu refers to Seisai (i.e. Keio Sosa 1863-1937), 12th generation head of Omotesenke, who's contemporary Seinyu was.

References:
Signature and seal of Seinyu, see: Encyclopedia of Signatures and Seals (落款花押大辞典 Rakkan Kao Daijiten), Kyoto 1982, p.1440.