The Winter 2016 Event Sortie! Operation Rei-Go is planned to start on February 10th, 2016. It has been confirmed that the event will be inspired off of Operation Rei-Go which was a one day battle that took place along the Mindoro Island where an IJN counterattack was conducted in the winter on December 26th, 1944.
The Event is planned to be a small scale event, which will allow you to choose a difficulty much like previous events. It's been noted that hard level difficulty will be more difficult compare to usual event maps.