17 events the sources record for this year, grouped by region.
What happened
China (11)
Emperor Duzong died in the Funing Hall; by his edict the crown prince Xian ascended the throne. (History of Song (Songshi), Annals 宋史卷046 咸淳十年)
Chancellor Bayan led one army toward Yingzhou; Marshal Sodu went toward the Huai, and Zhai, the pacification commissioner, went toward Jingnan. (History of Song (Songshi), Annals 宋史卷047 瀛國公)
The Yuan attacked Yingzhou; Commander Zhang Shijie defended it strenuously, and the Yuan withdrew through Tenghu and entered the Han River. (History of Song (Songshi), Annals 宋史卷047 瀛國公)
The Yuan attacked Yangluo Fort; Xia Gui defended it strenuously, but Wang Da, Commander of the Wuding Army, died in battle. (History of Song (Songshi), Annals 宋史卷047 瀛國公)
Cheng Pengfei and the acting commander Zhang Yanran surrendered by handing over the city. (History of Song (Songshi), Annals 宋史卷047 瀛國公)
Ordered fifteen thousand troops from the tuntian, Jurchen, and naval units, with nine hundred warships, to conquer Japan. (History of Yuan (Yuanshi), Annals 元史 卷8 世祖 1274年 3月)
When the army reached Ezhou, Song's Zhang Yanran, Wang Yi, and Lai Xingguo offered their cities and surrendered. (History of Yuan (Yuanshi), Annals 元史 卷8 世祖 1274年)
The Yuan send the General Chalhol to supervise the building of three hundred warships, and have all craftsmen, laborers and materials provided by our country. (Goryeosa (History of Goryeo) 世家 卷27 元宗 十五年)
October 1274: Governor-General Kim Bang-gyeong and others set out from Happo to attack Japan with 8,000 Goryeo troops, 25,000 Mongol-Han troops and over 900 warships (Goryeosa Jeolyo (Essentials of Goryeo History) 권19 元宗 十五年)
Japan (4)
After 11 days they reach Iki, where Japanese troops form ranks on the shore; Bak Ji-ryang and Jo Byeon pursue them and the Japanese ask for surrender (Goryeosa Jeolyo (Essentials of Goryeo History) 권19 元宗 十五年)
1st month, day 26: the throne passes to the Crown Prince; the new emperor is 8 (line 118, "Hachi ni narasetamaeba") (Masukagami 줄 118)
The planned procession on the 19th of the 11th month and Gosechi starting on the 20th are cancelled because of the Mongol alarm; no Daijoe kagura either (Masukagami 줄 122)
In the 10th month a Mongol force of about 10,000 invaded Tsushima and the steward So Sukekuni fell. They soon moved on to Iki, where the deputy governor Taira no Kagetaka fell. (Rai Sanyō, Nihon Gaishi part_07.txt 줄 79 (卷之四))