Portable keyboard tremolo musical instrument

A stringed musical instrument with finger-operable keys for playing tremolo notes, said instrument comprising:

• a hollow sound box with horizontal top that supports a plurality of metal strings tuned to the chromatic scale of musical notes of a range of about two octaves, said sound box of a size that can be conveniently carried and supported by a shoulder strap in a playing position by a player;
• a manifold attached by attachment means to the top of a sound box, from which manifold a plurality of finger-operable keys extend forward toward a player, and from which a plurality of hammers extend rearward to make contact near the midpoints of said strings;
• an apparatus associated with each key that actuates a hammer to play tremolo notes on a string when said key is pressed down in a single downward motion by a player's finger, said apparatus enabling control of frequency of tremolo by the distance that said key is pressed;
• a device associated with each key that quits the motion of a hammer when said key is released, said device stopping said hammer in a position that is a small distance over said string so that vibration of said string may continue unobstructed by contact with said hammer;
• and
• tilted mounting of said keys and of said hammers that assist a player in additionally varying the frequency of tremolo.