The main purpose of the bridge on an acoustic guitar is to transfer the vibration from the strings to the soundboard, which vibrates the air inside of the guitar, thereby amplifying the sound produced by the strings. On all electric, acoustic and original guitars, the bridge holds the strings in place on the body. There are many varied bridge designs. There may be some mechanism for raising or lowering the bridge saddles to adjust the distance between the strings and the fretboard (action), or fine-tuning the intonation of the instrument. Some are spring-loaded and feature a "whammy bar", a removable arm that lets the player modulate the pitch by changing the tension on the strings. The whammy bar is sometimes also called a "tremolo bar". (The effect of rapidly changing pitch is properly called "vibrato". See Tremolo for further discussion of this term.) Some bridges also allow for alternate tunings at the touch of a button.
Left-handed players sometimes choose an opposite-handed (mirror) instrument, although some play in a standard-handed manner, others play a standard-handed guitar reversed, and still others (for example Jimi Hendrix) played a standard-handed guitar strung in reverse. This last configuration differs from a true opposite handed guitar in that the saddle is normally angled in such a way that the bass strings are slightly longer than the treble strings to improve intonation. Reversing the strings, therefore, reverses the relative orientation of the saddle, adversely affecting intonation, although in Hendrix's case, this is believed to have been an important element in his unique sound.
Guitar chords are dramatically simplified by the class of alternative tunings called regular tunings. In each regular tuning, the musical intervals are the same for each pair of consecutive strings. Regular tunings include major-thirds (M3), all-fourths, augmented-fourths, and all-fifths tunings. For each regular tuning, chord patterns may be diagonally shifted down the fretboard, a property that simplifies beginners' learning of chords and that simplifies advanced players' improvisation. The diagonal shifting of a C major chord in M3 tuning appears in a diagram.
Another chord you come across every day, the E major chord is fairly straightforward to play. Make sure your first finger (holding down the first fret on the third string) is properly curled or the open second string won't ring properly. Strum all six strings. There are situations when it makes sense to reverse your second and third fingers when playing the E major chord.
Unlike many string instruments which use a bow to create a sound, guitars are played by plucking or strumming the strings on the instrument, which vibrate to create a sound. Chords are played when the guitarist holds their fingers down on more than one individual string to change its length, which in turn changes the frequency of the vibration created - in other words, it creates a different note. Performers often use guitar tabs, rather than sheet music, when learning music: this acts as a kind of 'map' to teach guitarists where to put their fingers on the strings.