Nintendo sank to a loss for the fiscal year ended March as sales of its Wii U game machine continued to lag, but the Japanese manufacturer of Pokemon and Super Mario games promised Wednesday to return to profit this year. Kyoto-based Nintendo reported a 23.2 billion yen ($229 million) loss, a reversal from a 7 billion yen profit eked out the previous year. Annual sales fell 10 percent to 571.7 billion yen ($5.6 billion). It did not break down quarterly numbers.