Today is 9-18, remembered by the Chinese as the anniversary of the 1931 Mukden Incident, in which Japan began its invasion of Manchuria on the pretext of securing the area after an explosion in a Japanese-owned railroad line; the bomb is generally believed to have been set by Japanese militants. From that date until 1945, Japan occupied varying amounts of China; at its height, Japan's control included cities and railroads ("lines and points") all along China's east coast. The bloodiest year was probably 1937, when Japan pushed down from Manchuria to take cities farther in the south, notably Shanghai and Nanjing (you may have heard of the "Rape of Nanking" or the "Nanjing Massacre").
More recently, last week the Japanese military confiscated a fishing boat and arrested its crew around the Diaoyu/Senkaku Islands, ownership of which is contested by China. So, Chinese nationalism being what it is and anti-Japanese sentiment having been pretty agitated recently, there has been a lot of speculation and media reporting about possible protests, particularly those being organized online. China's government, though, clearly doesn't want anything untoward happening; from what I understand, protests are almost always stamped out immediately here, and now would undoubtedly be a particularly bad time for the windows of the Japanese Embassy to get smashed in. According to the LA Times, in the past few days China's internet censors have been hard at work, deleting posts attempting to organize protests and even blocking all internet search results that mention of the islands in internet searches.
Either it worked, or the Chinese just don't care all that much after all. Beijing's protesters numbered in the dozens today, and the LA Times reports that they dispersed after marching from the Japanese Embassy to the Chinese Foreign Ministry earlier today; the largest group that I've seen reports on (in Shenzhen) was merely "over 100."
At any rate, late this afternoon I had nothing particular to do and had forgotten to bring the ID I needed to get a card at the National Library, so (semi-disregarding what the Light Fellowship, State Department, Yale, etc have to say about staying away from protests... oops), a friend and I headed over to the Japanese Embassy to check it out. Of the large, one-block foreign legation complex in which the Japanese Embassy (among many others) is situated, three sides were entirely ringed with policemen/PSB officers, with companies of military police at the key gates and intersections and marching around the perimeter. It was also pretty clear to me that there were a lot of plainclothes policemen around, especially at the intersection closest to the embassy. Police vans were everywhere. We were turned away at four points, though one we just sort of walked around because there was a second cordon farther up so nobody at the first one seemed to care a great deal.
On the way back, we sat down to rest (i.e., listen to the handful of Chinese onlookers standing outside the aforementioned first cordon waiting for something to happen), and I heard one of them say, "[he] hit a Japanese reporter. If I had been there of course I would have stopped him; let him (the reporter) [~take back news of] the rage of the Chinese people!"