TOKYO, May 21 (Reuters) - Japanese government bond (JGB) yields inched up on Tuesday, with long and superlong yields reaching decade-highs as investors sought more signals on the Bank of Japan's (BOJ) policy outlook.
Despite a lack of new catalysts, JGB yields continued to climb after the BOJ unexpectedly cut offer amounts at a bond-buying operation last week, putting the market on edge.
The 10-year JGB yield edged up 0.5 basis point (bp) to 0.980%, its highest since May 2013.
The 20-year JGB yield rose 1 bp to a more than 11-year high of 1.790%.
Market participants have been speculating about additional interest rate hikes, which some believe could come as soon as July, with the BOJ under pressure as the yen slides to 34-year lows against the dollar.
They also remain wary of further cuts to the BOJ's bond purchases ahead of another bond-buying operation on Thursday.
The second workshop in a comprehensive review of the BOJ's monetary easing tools taking place on Tuesday added to the sense of caution.
The central bank is expected to scrutinise the effects and drawbacks of its radical stimulus measures, making investors question its implications for bond-buying.
The discussion "should support or justify the normalization process, basically," said Naka Matsuzawa, chief macro strategist at Nomura.
The BOJ has been an aggressive buyer over the years to defend its ultra-low rate policy, pushing its ownership to around half the entire market.
Meanwhile, responding to questions about Japanese government bond yields hitting over ten-year highs this week, Japanese Finance Minister Shunichi Suzuki said it is important for the government to closely monitor the market and communicate with traders.
The two-year and five-year yields were flat at 0.340% and 0.575%, respectively.
The 30-year JGB yield ticked up 0.5 bp to 2.085%. (Reporting by Brigid Riley; Editing by Varun H K)
