The khim (Thai: ขิม ; pronounced "kim," with a rising tone, in Thai) is a hammered dulcimer from Thailand and Cambodia. It is made of wood and trapezoidal in shape, with numerous brass strings. It is played with two flexible bamboo sticks and is used as both a solo and ensemble instrument.

A boy playing a khimThe instrument was introduced to Thailand and Cambodia from China, where a similar (though usually larger) instrument is called yangqin; the khim produces a significantly softer sound. Traditional khim have two bridges, though in the late 20th century some players began using larger instruments with more bridges.

It is interesting that with the khim a clearly foreign, non Thai instrument today is among one of the most famous solo and ensemble instruments...

It is clearly a follower of the Chinese equivalent "Yang Qin" which surely derived from the Indian and Persian Santoor dulcimers, that were imported to China through the silk road and other trading routes.

The butterfly shaped box of the 42 stringed zither knows two rows of  seven frets/bridges, providing 21 tones and thus 3 octaves of a diatonic scale (which still can be pentatonic if used in an ensemble).

The left row is also beaten behind the bridges in order to resound the higher octave (which requires a precise tuning), thus presenting two octaves for the left hand and one octave for the right hand.