As a music theory expert with a deep understanding of the intricacies of musical keys, I can provide a comprehensive explanation of the concept you've inquired about. The question you've asked pertains to identifying the major key that has a single sharp. This is a fundamental aspect of understanding the circle of fifths and the construction of major and minor keys in Western music theory.

The circle of fifths is a visual representation of the relationships among the 12 tones of the chromatic scale. It is arranged in a circular pattern, with each of the 12 notes represented by a key signature that includes either sharps or flats. The circle of fifths is a powerful tool for composers, musicians, and theorists, as it helps to visualize the intervallic relationships between major and minor keys, as well as the number of sharps or flats associated with each key.

In the context of the circle of fifths, each major key is associated with a minor key that shares the same key signature. This is because the relative minor of a major key is found a minor third below the major key, and the key signatures of these two keys are identical. For example, the relative minor of C major is C minor, and both have no sharps or flats in their key signatures.

Now, let's address the question at hand: Which major key has one sharp? To answer this, we must consider the order of sharps in the key signatures as we move clockwise around the circle of fifths. Starting from the key of C major, which has no sharps or flats, we add a sharp for each subsequent key in a clockwise direction:


1. G major - This is the key we are looking for, as it has one sharp, which is F#. The relative minor of G major is E minor, and it also has one sharp for its key signature.


2. D major - Following G major, D major has two sharps: F# and C#.


3. A major - Continuing around the circle, A major has three sharps: F#, C#, and G#.


4. E major - E major has four sharps: F#, C#, G#, and D#.


5. B major - B major has five sharps: F#, C#, G#, D#, and A#.

As we can see, the pattern continues with each subsequent key adding an additional sharp. Therefore, the major key with one sharp is G major.

It's important to note that the concept of sharps and flats is relative. For instance, if we were to consider the circle of fifths from the perspective of flat signatures, we would start with C major (no sharps or flats) and proceed counterclockwise, adding a flat for each subsequent key:


1. F major - This key has one flat, which is B♭.


2. B♭ major - B♭ major has two flats: B♭ and E♭.


3. E♭ major - E♭ major has three flats: B♭, E♭, and A♭.


4. A♭ major - A♭ major has four flats: B♭, E♭, A♭, and D♭.


5. D♭ major - D♭ major has five flats: B♭, E♭, A♭, D♭, and G♭.

In this case, the major key with one flat is F major.

Understanding the circle of fifths and the relationship between sharps and flats is crucial for musicians who wish to improvise, compose, or analyze music. It provides a framework for understanding the harmonic structure of music and the tonal relationships between different keys.

In conclusion, the major key with one sharp is G major, and its relative minor, which shares the same key signature, is E minor. This understanding is foundational to the study of music theory and is a stepping stone to more advanced concepts such as modulation, harmony, and counterpoint.

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Thus G major (E minor) has one sharp which is on the F; then D major (B minor) has two sharps on F and C and so on. Similarly successively lowering the key by a fifth adds a flat, going counterclockwise around the circle of fifths.read more >>