Izanagi Denshou ~2010 Banki Tanjou~

In 2005 a man is found dead in the Tokyo park with the name of the village written on a note in his pocket. Main character is a researcher who combines pieces of information about the village and visits it, but villagers hate external visitors. It turns out that Imperial Army built the battleship "Darker Heavens" to turn the tides of the war. Now descendants of military families try to revive the idea and reconstruct the ship. The Prime Minister secretly orders to stop the growing revolt. Protagonist gets engulfed in the intertwined vortex of legends around the ship and those who seek it.

[From vndbreview]