This is a sister work to the clarinet octet "Pater Noster" (Brain Music / Bravo Music) written for the professional group NASCA Clarinet Ensemble in Nagoya."Stabat Mater" means "Stood the mother, full of grief". We were given a precise commission request from Mr. Koji Miura, a senior at Musashino Academia Musicae and member of the group. Seeking a work for both clarinet octet and a clarinet choir, the request was a piece to benefit repertoire development of the clarinet ensemble. The premiere was performed by all members of the NASCA Clarinet Ensemble.In addition, we received much advice from Hiroshima Symphony Orchestra clarinet player Shinsuke Hashimoto for this publication. We would like to thank you from the bottom of our heart.