Apart from starting a chord on the first degree of the scale, it is also possible to build chords on all the other notes of the major scale. A chord built on the second degree of the major scale would contain the 2nd, 4th and 6th notes of the scale.
A chord built on the third degree of the scale would contain the 3rd, 5th and 7th notes of the scale,etc. The chord building pattern always consists of the root note (original note), the note two ahead of that note, and the note two ahead of that note, e.g. C E G, D F A, E G B, etc. If you build chords on the first, fourth and fifth degrees of the major scale, you end up with chords 1, 4 and 5 which are the most common chords used for playing the Blues. Because of the pattern of tones and semitones in the major scale, not all the notes in these chords are comparatively the same distances apart. These different distances result in different types of chords such as minor chords and diminished chords. By adding more notes to the chords it is possible to create other chord types such as 7ths, 9ths and 13ths.
It is beyond the scope of this book to deal with all these chord types individually but if you are interested in how chords work, it is probably worth learning a bit of guitar or keyboard. This can also be beneficial in that you can quickly communicate with other musicians by understanding the terms they are using. Another major benefit of learning an instrument like guitar or keyboard is that you can accompany yourself. Many solo Blues and Folk performers use a harmonica rack worn around the neck in order to play guitar and harmonica at the same time. This method is great for your coordination and greatly increases your knowledge of the way notes and chords work together. Apart from this, its a lot of fun and means you are not dependent on other people to make music with. To learn more about chords, chord progressions and keys, see Progressive Complete Learn to Play Guitar Manual or Progressive Complete Learn to Play Keyboards Manual. For easy reference for playing Blues in any key, here is a chart showing chords 1, 4 and 5 in all keys.