Japan likely deployed $36.58 billion to purchase yen in the foreign exchange market, according to central bank data released Monday.
The figure represents the estimated cost of the latest intervention aimed at halting the yen's slide and restoring stability to the currency.
The Japanese yen strengthened to its highest level against the US dollar in more than two years following the move.
The sharp appreciation reflects the immediate impact of the massive liquidity injection into the market, signaling Tokyo's determination to defend the currency despite the significant financial outlay.
This action follows a broader escalation in efforts to support the yen, including direct intervention by the US Treasury Department.
Washington's involvement marks the first time the US has directly stepped in to bolster the Japanese currency since 2011, underscoring the severity of the depreciation and the coordinated nature of the response.