The big story in Asia affairs today is a little trip that was supposed to stay a secret: the dispatch of Isao Iijima, adviser to Japan's Prime Minister Shinzo Abe, to meet with senior officials in North Korea, thereby breaking the united US/South Korean/Japanese front in negotiations with Pyongyang.
It is the first instance of an overt divergence between Japanese and US diplomatic and security strategies, something that has been implicit in Japan's sometimes-inflammatory brand of nationalism under Prime Minister Shinzo Abe - and Abe's determination to move Japan beyond its traditional role of obedient
US ally to independent regional force.
The United States has been quietly disapproving of Japan's China strategy - witness Kurt Campbell's statement that the US advised Japan against nationalizing the Senkaku islands - and provocative nationalist hi-jinks on issues like the Yasukuni Shrine, but excused them as politically motivated exercises in domestic base-pandering.
However, the North Korean trip has revealed the cloven hoof beneath the robe, as far as Japan's independent aspirations in Asia are concerned.
Japan Times made it clear that the US was not consulted in advance about the trip; US special representative for North Korea Glyn Davies was only briefed after the visit:
Japan briefed the United States on Thursday about the surprise visit to North Korea by an adviser to Prime Minister Shinzo Abe.
After meeting with his Japanese counterpart in Tokyo, Glyn Davies, US. special representative for North Korea policy, said he hopes to gain more "insights" into Isao Iijima's unannounced trip in the coming days. ...
The trip, apparently an effort to resolve the issue over North Korea's abductions of Japanese nationals in the 1970s and 1980s, has raised concerns that Japan could be seen as acting alone, while the United States and South Korea continue to pressure Pyongyang over its nuclear arms and missile threats.
"I have begun the process of learning a bit more about [Iijima's trip]," Davies told reporters after meeting with Shinsuke Sugiyama, director general of the Foreign Ministry's Asian and Oceanian Affairs Bureau.
"I think we have some days to wait for all of us before we know there are any results from this mission ... we obviously will look forward to hearing from the government of Japan more details about this in [the] coming days," he said.
While South Korea has criticized the Japanese move as "not helpful," given the importance of coordinating a united front by Washington, Seoul and Tokyo against Pyongyang, Davies said, "I'm not going to address it in that way." 
The Christian Science Monitor calls it from the US side: "Japan's 'secret' trip to North Korea disrupts united stance against Pyongyang."  South Korea was less circumspect:
Seoul criticized Tokyo Thursday for dispatching an envoy to North Korea voicing concerns that the visit could undermine efforts to forge a coordinated approach toward Pyongyang.
Without prior notice to South Korea, Isao Iijima, an adviser to Japanese Prime Minister Shinzo Abe, arrived in Pyongyang spawning speculation that Japan might be trying to mend broken fences with the North, while South Korea, the US, recently even China, are making efforts to punish North Korea for conducting its third nuclear test in February by imposing sanctions.
"It is important to maintain close coordination, among South Korea, the US and Japan, toward North Korea," said [South Korean] Foreign Ministry spokesman Cho Tai-young in a media briefing. "In that sense, we think that the visit by Iijima to North Korea is unhelpful." 
According to Japanese sources, public revelation of the trip was something of a diplomatic fiasco maliciously inflicted by North Korea:
Japan speechless on PR chief's 'secret' N.K. trip
Blown mission reveals bid to sidestep trilateral denuclearization strategy for abduction issue.
The government is keeping mum on a secret visit to North Korea by one of Prime Minister Shinzo Abe's advisers after Pyongyang revealed it to the United States and South Korea.
We "can't reasonably explain" the visit because it was supposed to be kept secret, a government source said. ...
Only a handful of people, including Abe, Suga and Keiji Furuya, the minister in charge of the abduction issue, were involved in setting up the visit, they said.
A government source said there was no choice but to say: "I'm sorry, but I haven't been told about it at all," when a US official asked about Iijima's mission. 
It should be pointed out that secret trips to North Korea - in addition to outreach to North Korea's UN Mission in New York - are a common feature of US diplomacy.
Quite possibly, Abe believed his North Korean move would be granted equivalent secrecy by Pyongyang and Japanese diplomats could brief US diplomats with quiet pride after the fact concerning Japan's adept, confident exercise in unilateral diplomacy. If so, the media carnival unveiled by Pyongyang on the occasion of Iijima's visit revealed Abe to be rather naive, as North Korea leapt at the chance to highlight disarray in the anti-DPRK alliance.
Abe's decision to stir the North Korean pot has several elements.
The first is the desire for domestic political advantage. A breakthrough on the issue of the remaining Japanese abductees would be a feather in Abe's cap and help secure the electoral tidal wave in the July upper house elections needed to secure a two-thirds majority - and constitution revision clout - for the Liberal Democratic Party.
Second is a genuine and understandable awareness that Japan's foreign policy needs, both on North Korea in particular and Asia/China in general, have often played second fiddle to whatever grand strategy the United States is pursuing.
The "Nixon shock" of US outreach to China in 1972 is still remembered, especially among Japanese conservatives who remember it as a betrayal of the anti-communist ethos that was supposed to permeate US diplomacy. In 2007, Japan was humiliated when the US State Department undertook to resume discussions with North Korea following its first nuclear test, without even bothering to obtain North Korean lip service on the hot-button issue of the abductees.
So there is a definite sense that Japan has to look out for and advance its own priorities; for conservatives, that translates into a willingness to pursue an independent foreign policy while shrinking from overt conflict with US priorities (though Iijima's North Korean trip indicates that Japanese deference to US policy and face may be increasingly "honored in the breach" as it were).
Third and, perhaps, less appreciated, is Japan's desire to leverage its independent foreign policy into a decisive role in Asian diplomacy. Japanese unilateralism - and the demonstrated threat of Japanese unilateralism and even brinksmanship - ensures that the US has to grant Japan a de facto veto over US policies such as rapprochement with China and negotiations with North Korea in order to keep the increasingly assertive and independent Japanese government on board.
Fourth, Japan's conservatives apparently possess an atavistic desire to confound and humiliate South Korea for its pretensions to regional economic and diplomatic leadership.
As the celebratory circle jerk of stock market punters over the soaring Nikkei continues, it should be noted that for the first time since 1998 the growth rate of yen-weakened Japan will exceed that of South Korea.
Currently, South Korea has stated a noble commitment to addressing its economic difficulties through stimulation of domestic demand, thereby letting Japan reap the unilateral benefits of a weak-yen policy. However, as South Korean corporate profits erode - and if South Korea's financial markets are roiled by hot money released by Japanese quantitative easing - it is an open question as to how long South Korea will take a generous view of Japan's lunch-eating/middle-finger flourishing attitude toward its neighbor.
There are already rumblings that South Korea is facing a Japan-style aging/stagnation crisis that Keynesian pump-priming is ill-equipped to address. If so, domestic pressure will grow for the Korean government to take Japan-style countermeasures and export its own miseries-presumably to China - with quantitative easing and a weakening of the won.
Then it will be up to China to hold the line and decide if its growth prospects are strong enough to meet the challenge with greater productivity and efficiency - or take the easy route of devaluing the yuan (employing the universally sanctioned fig leaf of "quantitative easing") and drive the Asian economy into a ditch.
In an article excoriating Japan's approach to North Korea, Korea Times' Kim Tae-gyu detoured into trade and economic grievances:
Abe's flagship economic policy of depreciating the country's currency to boost the price competitiveness of made-in-Japan products is also under criticism as it tries to galvanize its economy at the expenses of its neighbors.
Critics say the Abe administration's large-scale monetary easing and the resultant fast devaluation of the yen are tantamount to economic aggression toward Asian nations.
The weakening of currency of the world's No 3 economy spills over to its rivals in international markets such as Korea and China whose exporters are now panicking - it is the very essence of a "beggar-thy-neighbor" policy.
The yen was traded near a historical high of 78 yen to the dollar last year but it now fluctuates in the vicinity of 100. Many global agencies expect that the depreciation is only halfway done as it is likely to further rise to around 120 yen by the end of next year.
The weakening yen has breathed fresh life into its moribund economy, which experienced a two-decade slump. By contrast, Korean and Chinese exporters that compete with Japanese ones are complaining about their substantially reduced bottom lines. 
From the US point of view, South Korea and China lining up to protect their interests against predatory Japanese trade policy - on top of Japan alienating South Korea with its go-it-alone North Korea initiative - is not what the US pivot/rebalancing to Asia is supposed to be all about.