This comes as Japanese yields continue to nudge higher all through this week, with 10-year JGB yields touching 0.77% today:

JGB10Y
10-year JGB yields (%) daily chart

Since the BOJ allowed for yields to roam above the 0.50% mark, bond sellers haven't really let up and I reckon that policymakers still want to manage expectations somewhat so as to not let it roam towards the 1.00% mark too quickly.