Pairs Trading: Reversion to the Mean

Hello everyone!
I started to move towards statistical arbitrage and pair trading. As it seemed, there are a lot of opportunities for trading in Forex both within the day and in the medium term.
I have read all similar topics on the forum and I can say that using MT4 for calculations and building an analytical system is not the best option. I am using python for calculations and visualization.
For myself, I realized that the main idea in pair trading is the convergence of the divergence of pairs.
For example, now I see a good opportunity for pairs usdjpy and usdchf. I think now is the time to buy usdchf and sell usdjpy. In the near future, these pairs will clash.

That's mean you are going to sell/buy at the same time USD.
It's a bit strange.

On the chart above you can see usdjpy and usdchf. They move together all time, but now we see a huge divergence between them. And I think, usdjpy is overvalued and usdchf is andervalued. They will move to their median price.

P.S. I am not a native. Sorry for my grammar.