Japan’s Olympic champion Haruka Kitaguchi took silver with 62.70m. Compatriot Sae Takemoto was third with 62.15m.
The 18-year-old from Ningbo needed only one legal attempt. Kitaguchi had beaten her at the World Ultimate Championship in Budapest. Yan answered in Nagoya by clearing 70 metres immediately and leaving the rest of the field more than seven metres behind.
Yan set a world under-20 and Asian record of 71.74m in Xiamen in May, the second-longest throw in history behind Barbora Špotáková’s 72.28m world record. She won the Diamond League meetings in Xiamen, Oslo, Paris and Monaco, then the Brussels final with 68.42m.
She was world under-20 champion in 2024. Sunday’s gold is her first Asian Games title and comes two years before the Los Angeles Olympics, where she will be among the favourites.
Kitaguchi, Paris 2024 Olympic champion, could not answer the opening throw. Takemoto completed a Japanese two-three behind the Chinese teenager.
Yan’s season has been built on first-round statements. Nagoya was the same pattern: one throw, a Games record, and the rest of the competition chasing a mark they never reached.