Are you using a metronome when you are practicing? Yesterday, I opened the metronome app on my phone and the display was so dark… there was only one yellow ball in the black screen ! I thought my phone broken but … it says “Jugoya” in Japanese, which means “The Night of the Harvest Full Moon”. It was a very special moon celebration day! Even though I can't see the numbers well, the full moon was moving correctly and practiced with me. Let's practice with a metronome and don't miss any special display! ;)