Gitori's Find the Notes game challenges users to find a given note in a highlighted area of the fretboard. Over the last 3 years, the game has been played by over 10,000 people, and I've collected 275,169 different data points on note identification. Based on that data, I have a heatmap of the hardest notes to identify on the fretboard. Reds are the hardest and greens are the easiest.