Japan’s core machinery orders grew in March for the first time in two months but they are seen slipping in the current quarter, suggesting that weak capital spending could further sap momentum from an economy struggling to rebound from a recession. The 2.9 percent month-on-month rise in core orders, a highly volatile data series regarded as an indicator of capital spending in the coming six to nine months, beat economists’ median estimate of a 1.8 percent gain, Cabinet Office data showed on Monday.