The Kitamae Ships sold kelp of Ezochi (Hokkaido) in the area along the Sea of Japan, Seto Inland Sea and Osaka. There was a trading route from Ezochi, Nagasaki to China. And another trading route was Satsuma (Kagoshima) to Qing (China) via Ryukyu (Okinawa). Those two routes together were called "Kelp Road".

The Satsuma and the Choshu Alliance played important roles for the Meiji Restoration.　Shimonoseki of the Choshu Clan (Yamaguchi Pref.) greatly prospered by the Kitamae Ship trading. People called Choshu "Naniwa (Osaka) in west" also prospered.