The Koan War temporarily halted the trade; however, the quasi-official trade relationship came to be established since Japan promoted the trade actively by dispatching the trading vessels, Kenchojibune (the trading vessels dispatched to cover the costs of repair and construction on Kencho-ji Temple) and Tenryujibune (the trading vessels dispatched to cover the costs of repair and construction on Tenryu-ji Temple), to Yuan Dynasty in order to raise funds to build a temple or a shrine with permissions of the Japanese Imperial Court and the Kamakura bakufu (Japanese feudal government headed by a shogun) in the end of the 13th century while increasing the guard against Yuan Dynasty.
弘安の役はこれを一時的に中断させたが、13世紀終わりには日本の朝廷や鎌倉幕府の許可の下に勧進活動を名目とした寺社造営料唐船（建長寺船・天龍寺船など）が派遣されるなど、日本側は元に対する警固体制を強化しつつも貿易については積極的にこれを奨励したため、準公式な貿易関係も成立するようになった。