The name Ginga is simply Japanese for "galaxy," as it was discovered by the in 197102 CE.
The galaxy is much larger than the Milky Way with 300 billion stars compared to the Milky Way's 100 billion.
The oldest civilization, The Cristallus Noocracy, was founded in about 120000 CE. This civilization expanded to control about two-fifths of the galaxy.
Blicu was founded in 192349 CE, and expanded to take up about a tenth of the galaxy.
The arrived in 191702 CE and expanded to control a third of the galaxy. Nihon conquered about twelve smaller civilizations to fuel their expansion.