Matenrou Opera has just announced on their official Twitter(
http://twitter.com/MatenroOpera) that Sono has influenza, and as a result, the concerts on 1/15(Morioka), 1/18(Sapporo) and 1/20(Sendai) will be postponed. They say that more information should be available at their official site shortly. I have work tomorrow, so I am going to sleep, but I will post all updates later on tomorrow or whenever it becomes available.