Noob Question

https://preview.redd.it/igy54km5naoe1.png?width=1228&format=png&auto=webp&s=2e80b6820ab94287e1d23eb973927b3561feb2c5

I noticed in Hiradoumi's match with Takerufuji that Hiradoumi launched before Takerufuji could touch the ground. Takerufuji was reaching to the ground a bit slowly, so I'm just curious what the rule is in this situation. My basic understanding was that both rikishi touch the ground before engagement. So, was this a foul by Takerufuji?