Zipang, Gate: Jieitai Kanochi nite, Kaku Tatakaeri Recommendations
Both follow the same theme. What will happen when a future civilization meet a civilization from the past?
While Zipang take it more seriously both shows are quite similar. The Gate feature fantasy and lot of comedy in between scenes while Zipang is more realistic, gate does have more mature/violent scenes while it looks more friendly.
If you like anime where that the main cast is far superior and beat the shit out of their enemy it is a good show to enjoy without relaying on too much of superpowers, but advancement in science. I guess?
Both series features modern japanese military servicemen time travel to less developed parallel dimension/world.
But while in Zipang they travel to WWII-times parrallel dimension of our world, in Gate they being sent to a late medieval fantasy world.