The keyword has a poetic irony. The battle was forgotten for two reasons:

Despite its significance, the Battle of Surabaya, or Sub Indo, remains a relatively forgotten chapter in the history of the Indonesian National Revolution. While it is still commemorated in Indonesia as a heroic moment in the country's struggle for independence, it is not as well-known globally as other battles in the region.

). But they had the ghost of the land on their side. As the Dutch column entered the narrow pass, Surya gave the signal—not a shout, but the low, mournful whistle of a bird. The silence broke.