It's a Japanese Arisaka Type 38 from WWII, made by Tokyo Kokura Arsenal and chambered in 6.5*50 mm SR. It is hard to determine the year of making as Japanese has very different system in documenting their rifles, but I bet it is an early-mid war version. What is missing is a dust cover that goes on top of the bolt, which prevents dirt/dust gets into the bolt (It was thought kinda useless and Japanese soldiers ditched them away during action).
This one is quite well preserved as the mum (the sixteen-petal chrysanthemum stamped above the two vent holes) has not been ground. Often Japanese soldiers were ordered to remove that mum after they surrendered, as the mum is the symbol of the Japanese Emperor, who owned all the guns, and was considered divine. The Japanese could not tolerate the emperor's symbol being given up in surrender, so it had to be defaced. If the mum has not been ground then it probably mean this rifle is a vet brought back from the soldier who was killed, rather from the POWs.