The brownest of the Asian grasshopper-warblers, with the least contrasting brow stripe and darkest underparts. Breeds in dense grassy areas on small islands off the coasts of Japan, far eastern Russia, and the Korean Peninsula, where it may be seen perched on the top of a bush singing. On its wintering grounds, it can be found (with great luck) in various areas with dense vegetation cover, including mangroves, overgrown gardens, and shrubby patches. Song is simpler than that of other grasshopper-warblers, usually just one repeated note.