Is the Nikkei just a play on the Yen at this point?

Been watching the Nikkei with keen interest lately. On one hand, you have the government and BOJ pushing for inflation and trying to move away from the deflationary spiral. On the other, the recent moves in the Yen feel like they're heavily dictating the index's direction, almost more than domestic fundamentals. It's making me wonder if trading the Nikkei itself is just a proxy for a JPY forex play for a lot of international capital right now. I mean, we've seen some impressive gains, but how much of that is genuine underlying strength in Japanese corporates versus simply the currency making exports cheaper or flattering earnings for foreign investors?

It feels a bit oversimplified to say the entire market hinges on one variable, especially with the depth of the Japanese economy. But looking at the charts, the correlation is pretty striking. What are others seeing? Am I missing a bigger picture here, or is this becoming a dominant theme? Push back on this if you disagree.