TOKYO, July 19 (Reuters) - Japanese government bonds edged down slightly on Wednesday, with activity thin as investors awaited the outcome on Thursday of the Bank of Japan's policy meeting.
The 10-year cash JGB yield rose half a basis point to 0.070 percent, while the September 10-year JGB futures contract finished 0.04 point lower at 150.13.
In the superlong zone, the 20-year JGB yield and the 30-year JGB yield both inched half a basis point higher to 0.585 percent and 0.865 percent respectively.
The 5-year JGB yield was flat at minus 0.055 percent.
BOJ policymakers will conclude their regular meeting on Thursday, at which they are expected to upgrade their economic growth forecasts but cut their optimistic inflation outlook, sources say.
A majority of economists polled by Reuters expect the BOJ to once again extend the timeframe in which it will achieve its 2 percent inflation target.
Japanese manufacturers' and service providers' business confidence held steady at high levels in July, a separate Reuters poll found on Wednesday, underlining the central bank's upbeat view on the economy.
(Reporting by Tokyo markets team; Editing by Eric Meijer)