After a series of Mongol invasions of Korea between 1231 and 1281, Goryeo signed a treaty in favor of the Mongols and became a vassal state. Kublai was declared Khagan of the Mongol Empire in 1260  and established his capital at Khanbaliq  in 1264. Japan at the time was ruled by the Shikken  of the Hōjō clan, who had intermarried with and wrested control from Minamoto no Yoriie, shōgun of the Kamakura shogunate, after his death in 1203. The inner circle of the Hōjō clan had become so preeminent that they no longer consulted the council of the shogunate ), the Imperial Court of Kyoto, or their gokenin vassals, and made their decisions at private meetings in their residences ). The Mongols also made attempts to subjugate the native peoples of Sakhalin—the Ainu, Orok, and Nivkh peoples—from 1260 to 1308.

Question: How many years after Kublai was declared Khagan of the Mongol Empire did he establish his capital at Khanbaliq?
Answer: 4

Question: Which happened first, the death of Minamoto no Yoriie or the series of Mongol invasions in Korea?
Answer: death of Minamoto no Yoriie

Question: How many years passed after the death of Minamoto no Yoriie before the series of Mongol invasions in Korea began?
Answer: 28

Question: How many years did the Mongol invasions of Korea last?
Answer: 50

Question: How many native peoples of Sakhalin did the Mongols subjugate?
Answer: 3

Question: How many years did Kublai take to establish a capital after becoming Khagan?
Answer: 4

Question: How many years did the Mongol invasions of Korea last?
Answer: 50

Question: After Kublai was declared Khagan, how many years passed until he established Khanbaliq?
Answer: 4

Question: How many native tribes of Sakhalin were there?
Answer: 3

Question: Who had controlled Japan prior to the Hojo clan?
Answer: Minamoto no Yoriie

Question: For how many years did the Mongol invasions last?
Answer: 50

Question: For how many years did the Mongols try to subjugate native people of Sakhalin?
Answer: 48

Question: How many years was the overlap of the Mongol invasions and the Mongol attempts in Sakhalin?
Answer: 21

Question: How many years after Kublai was declared Khagan of the Mongol Empire did he establish his capital at Khanbaliq?
Answer: 4

Question: How many years did the series of Mongol invasions of Korea take place?
Answer: 50

Question: How many years did the Mongols attempt to subjugate subjugate the native peoples of Sakhalin—the Ainu, Orok, and Nivkh peoples?
Answer: 48

Question: Which two rulers ruled at the same time period?
Answer: Kublai