The recipient's name is 左古田常喜 Sakota Tsuneki, and 祈武運長久 ”Hope your eternal good luck in battle" is the only one slogan. The rest are all signatures. I suspect the authenticity, though. The ratio between the width and height of the flag doesn't seem correct to me. The same goes to the ratio between the red circle and the whole flag, or the position of the honorable title 君.