If there is one major currency pair worth keeping a closer eye on over the next couple of days, it is USD/JPY.The currency pair is trading back to around 157 after the yen fell roughly 2% last week, despite the BOJ raising its policy rate by 25 bps to 1.25%.The rate hike itself wasn't enough. Two dissenting votes, albeit from Takaichi-appointed members, and little urgency from governor Ueda over what comes next left traders questioning how quickly the BOJ will tighten further from here.Meanwhile, the dollar side of the equation remains supportive. The Fed's more hawkish tilt has lifted US rate expectations, with markets now assigning meaningful odds to another hike in October. The bond market is also keeping traders on edge, with 10-year Treasury yields hovering just below 5%.And that dollar support is starting to show up clearly on the USD/JPY chart as well.The pair has staged a solid rebound since bottoming out earlier this month just below the 153.00 level. And the push higher last week took out the 155.00 mark as well as the 50.0 Fib retracement level of the swing lower in September at around 156.64.The next immediate technical test sits around the 61.8 Fib retracement level at around 157.52, before the 200-day moving average (blue line) at around 158.39 comes back into view. The Friday high threatened a push above the former but buyers ran into offers near 158.00 before settling back lower.In starting the new week though, Japan being on holiday adds another complication.Trading conditions are thinner with Japanese markets closed, and that can exaggerate moves if momentum starts building. But more importantly, authorities have already shown this year that a holiday is no obstacle to intervention.Back during 4 May and 6 May, Japan's ministry of finance bought yen during the Golden Week holiday as part of its ¥11.7 trillion of intervention between late April and May.Looking to the price levels above, I wouldn't classify 158 or 160 as an automatic trigger for intervention. After all, Japan has consistently focused its language on excessive volatility and disorderly moves - rather than defending one fixed price.I reckon the speed of the next USD/JPY move would be more important than the level itself.A slow grind towards the 158 level per se may likely bring on more verbal warnings. However, a thin-liquidity surge through 157.50 and towards the 160 mark would be a very different proposition. That would be especially uncomfortable with traders already sensitive to rate checks and Japan's recent willingness to step into the market.MUFG also sees scope for USD/JPY to gradually grind higher in the near-term but gains may stay capped the closer it gets to 160.00:"We see scope over the near-term for the US dollar to advance further versus the yen. The reaction to the BOJ communications and Ueda’s press conference highlighted the fact that current market pricing may have become excessive. Near-term USD/JPY could advance further but the rates curve is reasonably priced and further hikes and intervention risks will curtail the scope for the move higher in USD/JPY. We would still expect USD/JPY buying to fade ahead of a break above the 160-level." This article was written by Justin Low at investinglive.com.