Charts. Courbet, Port. Approaches to Port Courbet and interior channels between Kakba Island and Pakha Pass, Tonkin Gulf, Tonkin, French Indo-China, from latest French surveys; with inset, Pakhunum Anch., from French survey in 1880, with corrections in 1913; chart 3162. Natural scale 1:146,706 at lat. 20° 50′.