Just as the doom-and-gloom stories about the Chinese stock market were reaching a fevered pitch comes this: China stocks just had their best day in six years, reports the Wall Street Journal. The Shanghai Composite rose nearly 6% and the smaller Shenzhen market about 4%. But don't celebrate too much: Reuters says the rebound was the result of the "most drastic" government move so far—the nation's securities chief barred shareholders who hold large stakes in companies from selling—and warns that the "costs of heavy-handed state intervention are likely to weigh on the market for a long time." And with about half of all stocks on the two markets suspended, it's not clear whether the Beijing moves will be "enough to reverse the broader selloff," notes the Journal. (More China stories.)