It was such a sudden announcement that both the Japanese and South Korean governments expressed surprise, and this act was viewed by some in Japan as retaliation for the establishment of 'Takeshima Day' in Shimane Prefecture, which happened just before the Korean proclamation.
突然の報に日本と韓国政府は驚きを見せたが、直前に島根県が制定した『竹島の日』への報復的な意味合いがあったと見られる。