The Bank of Japan is certain to raise rates further. The question is when

The Bank of Japan is widely expected to stick to its monetary policy tightening campaign as inflationary pressures in its capital city of Tokyo reaffirm the bank's economic projections. But market participants remain divided over the timing of the next hike. 

"My money is on another rate hike in October," Stefan Angrick, senior economist at Moody's Analytics, told CNBC via email. He predicted that hike would be followed by at least one more in 2025, possibly as early as January. 

Japan is likely to continue seeing "jumpy" inflation in the near term, Angrick said, noting government efforts to trim energy subsidies. While Prime Minister Fumio Kishida has pledged to extend support for household utility bills, he acknowledged these measures "cannot continue forever."

Kazuo Momma, a former BOJ official and currently executive economist at Mizuho Research & Technologies, however, expects the central bank to keep the rate unchanged in October. His base case includes a hike in January to 0.5% and a further hike to 0.75% in July. Momma said that would take Japan's monetary policy to its final position in this tightening cycle.

On Friday, data showed headline inflation for Japan's capital city of Tokyo accelerated to 2.6% in August from a year earlier, faster than a 2.2% climb in July. The core inflation rate, which strips out volatile costs of fresh food, rose 2.4% from a year ago. That's faster than the median market forecast and the July reading of 2.2%, accelerating for the fourth straight month.  

Still, Momma said "the momentum is not strong enough" yet for the BOJ to hike rates. As the central bank monitors global financial market risks, he said the BOJ does not "have a good reason to rush at this moment."

The upbeat monthly CPI