Sentiment among large manufacturers improved for the first time in three quarters in June, a Bank of Japan survey showed Wednesday, in a positive sign that runs counter to indications of a slowing economic recovery.

The Tankan big manufacturer index rose to 15 from 12 in March, beating economists' forecasts for an unchanged reading. The index is projected to improve to 16 in September, with large companies across all industries planning to boost capital expenditure by 9.3 percent in the year through March 2016, the BOJ said.

Improved business sentiment could help buttress an economy that BNP Paribas SA says may have slowed this quarter on weaker production and exports. The challenge for Prime Minister Shinzo Abe is to get companies to follow through on their investment plans and plow more of their record cash hoard into the world's third-biggest economy.