The detail that matters most for the Bank of Japan is base pay. Regular wages holding steady near 4% points to durable wage growth rather than a bonus-driven spike, which is the kind of evidence policymakers want before tightening further. That supports the yen and front-end Japanese government bond yields at the margin, even as the headline real wage gain slowed. The risk to the real wage picture comes from prices. With the inflation measure used in the calculation only just above 2%, and Tokyo core inflation accelerating alongside elevated oil costs from the Middle East conflict, any pickup in the deflator would quickly erode real gains. That tension matches the Reuters Tankan earlier today, where service firms said inflation was squeezing household purchasing power despite rising pay.- Japanese workers are still getting ahead of inflation, and steady base pay growth gives the Bank of Japan another reason to keep raising rates.Summary:Japan's inflation-adjusted real wages rose 1.5% year on year in August, the eighth consecutive monthly increase, slowing from a revised 2% in JulyTotal cash earnings rose close to 4% to about 311,000 yen, slower than a revised 4.3% in JulyBase salaries also grew close to 4%, matching July's pace, while overtime pay growth picked up to around 5% from 4.5%Special payments, mainly volatile one-off bonuses, were flat after rising around 5% in JulyThe inflation measure used to calculate real wages held just above 2%, below about 3% a year earlierJapan's real wages rose for an eighth straight month in August, government data showed on Wednesday, extending a run of gains that supports the case for further interest rate increases by the Bank of Japan.Inflation-adjusted pay rose 1.5% from a year earlier, slower than the revised 2% increase recorded in July. Average nominal wages, measured as total cash earnings, grew close to 4% to about 311,000 yen, down from a revised 4.3% rise the previous month.The slowdown in headline earnings came largely from bonuses. Special payments, which are mostly one-off and tend to swing sharply from month to month, showed no growth in August after rising around 5% in July. Underlying pay was steadier. Base salaries, or regular pay, rose close to 4%, the same pace as in July, while overtime pay growth accelerated to around 5% from 4.5%, a sign that firms are still working staff harder.The inflation measure the labour ministry uses to calculate real wages held at just above 2% in August, unchanged from July and well below the roughly 3% rate a year earlier. That lower deflator has been a key reason real pay has stayed positive.The data adds to evidence that Japan is moving toward the sustained cycle of rising wages and prices the central bank has sought for years. The BOJ raised its policy rate to 1.25% in September, and Tokyo core inflation accelerated in September at its fastest pace in 10 months, strengthening the argument for further tightening.Not all signals point the same way. A Reuters business survey published earlier on Wednesday showed sentiment among Japanese service companies falling sharply, with retailers and food producers saying inflation was eroding household purchasing power. Bank of Japan board member Ayano Sato, who opposed September's hike, also said this week that she favours raising rates gradually, without a pre-set pace.Whether real wage gains can be sustained will depend on prices. With oil costs elevated by the Middle East conflict, a faster rise in inflation would narrow the margin by which pay is outpacing living costs. This article was written by Eamonn Sheridan at investinglive.com.