“There is no well-established dictionary that includes the neologism and dialects that are commonly seen in Japanese novels. You can only resort to bringing questions to Japanese people. This is too much trouble,” he wrote.

He also said: “The effort required to master sufficient language skills to read a Japanese novel is no less than that of mastering a western language.” He then recommended Tao to learn a European language instead, as “Europe has masterpiece literatures”.

Song Hao, a senior marketing manager of China Guardian Auctions, on Thursday told the that the high price was not unusual for such a letter. She attributed the staggering price to the scarcity of Lu Xun’s handwritten letters and the extensive citation of it in other collections of his literary works.

Auctions of letters by late notable figures have been picking up this year. Earlier this year, Lu’s handwritten draft of his collection of ancient stories was sold for 6.9 million yuan. Two letters each from Chen Duxiu and Li Dazhao, two founding fathers of the Chinese Communist Party, were sold for 2.4 million and 4.14 million yuan respectively.

Lu Xun was the pen name of Zhou Shuren, who is widely proclaimed as one of China's most influential modern writers in the early 20th century. He is best known for being a profound critic who used irony to criticise Chinese social problems and national character. He showed sympathy to communist ideas and was highly acclaimed by the Communist regime.