Got this weird japanese toast messages. how can I trace which app is generating them?

Hi there. I keep getting any now and then some toast messages in japanese which seems to send some packets from my phone. here they are

I'd show you the screens but the forum prevents me to post images right now

I've got a Moto G 3rd Gen, running latest android 6.0
I listed all the apps running in my phone but none seemed suspect, just usual stuff from the play store.
can you help me identify is this is a malware sending some data from my phone? I totally have no clue