Although restoration of the pre-deflation price level by means of a price-level target might be a reasonable interpretation of the BOJ's price stability objective, I would not want to push the purely legal argument too far.
In its short existence, the working group has recorded two prominent achievements. The first is the choice in September 2018 of the ECB’s overnight rate as the new euro risk-free rate. This decision provided clarity to market participants and planning certainty for the transition towards more robust benchmarks in the euro area.