President Lee Myung-bak’s visit to Dokdo on Friday was a surprise in light of his consistent efforts since inauguration to build future-oriented ties with Japan. The unexpected visit ― the first ever by a Korean president ― is certain to throw the bilateral relationship into a tailspin as Tokyo views it as a breach of an unwritten understanding between the two nations.

Yet it is fully understandable given Tokyo’s repeated sovereignty claims to South Korea’s easternmost territory. During Lee’s tenure, Japan has made more provocations over Dokdo, a group of rocky outcroppings in the East Sea, than it did during the term of former President Roh Moo-hyun, who went over the top to check the neighbor’s unwarranted territorial ambitions.

In recent years, Japan has taken increasingly shameless moves to assert its ownership of Dokdo. Japan illegally incorporated the islets as part of its territory in 1905 before colonizing the entire Korean Peninsula. Korea has been in effective control of them since its liberation in 1945.

Last month, Japan renewed its claims over Dokdo, which it calls Takeshima, in its 2012 edition of the defense white paper. The annual paper has made this unfounded assertion since 2005.

Last week, Tokyo even went so far as lodging a protest against the Seoul government for stating the plain truth in its latest diplomatic white paper: Dokdo is indigenous Korean territory. To our dismay, it had the audacity to demand that Seoul retract the statement.

In March, as in the preceding years, Tokyo approved new school textbooks offering a distorted account of the facts about Dokdo. Tokyo’s ill-advised textbook authorization policy is truly disturbing as it forces young Japanese students to learn a twisted version of history and develop an erroneous view of Japan’s relations with Korea.

Given Japan’s unabashed attempts to lay claim to Dokdo, Lee’s visit was the right thing to do. Yet it was belated. He should have acted earlier as his policy of maintaining amicable ties with Japan to pursue mutual prosperity actually emboldened the wily neighbor to put forward preposterous territorial claims.

By making a landmark visit to Dokdo, Lee has shown to the world that the islets are part of Korea’s territory. He has also demonstrated his commitment to safeguarding national sovereignty and territorial integrity.

Yet it would be a grave mistake for him to think that his one-time visit would resolve the matter once and for all. If anything, his trip has moved the issue into a new phase by triggering more determined efforts from Tokyo to highlight its sovereignty over Dokdo.

Following Lee’s trip, Japan’s foreign minister said Tokyo would seek to take its territorial row with Seoul to the International Court of Justice. This move is not a great threat to Seoul in itself, because the ICJ cannot take any action without the agreement of both nations in a contested case. Seoul has rightly snubbed Tokyo’s move, precluding the possibility of the court taking up the issue.

Yet Tokyo will explore other ways to bring the dispute to the attention of the international community. As a result, Dokdo will increasingly be seen as a territory whose sovereignty is in dispute.

The Seoul government has long pursued what is dubbed a “quiet diplomacy” over the Dokdo issue. The approach calls for Seoul’s restraint in responding to Japan’s provocations on the grounds that overreaction would only serve Japan’s intention to escalate the dispute over Dokdo.

Yet Korea will find it increasingly difficult to follow the low-profile approach. Like it or not, Dokdo has already become a disputed area. Hence, Seoul now needs to change course and face up to Tokyo’s expected offensive in the international arena.

The government also needs to take steps to strengthen Korea’s effective control over Dokdo. Among other things, it will have to consider stationing marines on the islets, if Tokyo continues provocative activities.

Military authorities are also required to prepare for saber-rattling by Japan. As it did in 2005, Japan could send aircraft or ships near Dokdo out of its resentment over Lee’s visit and to draw global attention to its friction with Korea.

Whatever Japan does, one indisputable fact is that Dokdo belongs to Korea. Tokyo needs to realize that its repeated claims to Korean territory simply lay bare its inability to depart from its imperial past and to enter into a future-oriented partnership with Korea.