Why did Sun Yat-sen flee to Japan after the Second Revolution failed?

After the failure of the Second Revolution in 1913, Sun Yat-sen fled to Japan to escape the political consequences of his opposition to Yuan Shikai, who had reportedly instigated the assassination of Nationalist Party leader Song Jiaoren.

While in Japan, Sun sought to secure Japanese aid for his cause by promising significant concessions in China. However, his time there was marked by political difficulties, as he alienated many of his fellow revolutionaries by requiring them to take an oath of personal allegiance to him.1