Flag of Germany: Flag of Germany, horizontally striped flag of black, red, and gold (golden yellow); when used for official purposes, it may incorporate a central eagle shield.
Most of the websites i have looked at, say that the frequency of middle C note is approximately 261.626 Hz. and that middle C on guitar is at the 5th string 3rd fret. but my tuner says the frequency at the 5th string 3rd fret is 130.81 Hz.
The sound with frequency 440Hz is called here A1. The sound which is an octave lower is called A and has the frequency of 220Hz. We define the other names below. Note that 130.8Hz x 1.05946 = 138.6Hz which means that the interval between C and C# is one semitone. It is also one semitone between C# and D, D and Eb, Eb and E, and so on.