Japan’s annual exports in January jumped the most since late 2013 in an encouraging sign a weak yen is finally boosting the nation’s all-important export engine and helping the economy crawl out of recession. A pickup in shipments – which had been a soft spot in the economy – is welcome news for policymakers who hope exports will offset still-weak private consumption, and cheaper oil prices will spur firms to spend more on wages and investment, generating a virtuous growth cycle.