If you ask which country in the world most urgently needs amphibious equipment, it has to be the Rabbits. Hence, Tang Mo didn't even need to search on purpose; he could easily find a whole bunch of amphibious equipment from the Rabbits' pocket.
In those days, the Rabbit's amphibious landing divisions were under Uncle Eagle's tutelage, which is definitely beyond the expectation of many. The young and promising Kaisen II purchased many armored vehicles from Uncle Eagle that were never shipped back to his country.
Some of these armored vehicles were directly used to fight the Rabbits back then, while those in poor condition had their parts scavenged and were thrown away as scrap metal into recycling stations.
After the Rabbits' million-strong forces crossed the great river, they found these discarded scraps in the recycling stations and, lamenting the waste, picked them up to use for themselves.