The embassies sent to Tang China were also called "the four ships," and in the heyday of such embassies the envoy's party numbered over 400 people, which is how they reached the scope of having four embassy ships; by comparison, the thirteenth embassy could be said to be rather small in scale.
遣唐使は『よつのふね』とも呼ばれ、全盛期は400人以上、遣唐使船4隻という規模であったことから、この第13次遣唐使は比較的小規模であったと言える。