"FXBTCJPY" is a special product and does not strictly work with spot price.
Because of the extremely "peculiar" price, it often deviates from the spot price.
This is an indicator to confirm it.
In true TradingView spirit, the author of this script has published it open-source, so traders can understand and verify it. Cheers to the author! You may use it for free, but reuse of this code in a publication is governed by House Rules. You can favorite it to use it on a chart.