The koa wood 0-18K was introduced in 1918 as one of C.F. Martins first true steel string guitars and it came at a time when Hawaiian music was enjoying unprecedented popularity both in the Islands and on the mainland. The trend had begun in 1912 with a Broadway show, “Bird of Paradise,” and was followed in 1915 with the Panama-Pacific International Exposition in San Francisco, where Hawaii hosted a pavilion. The exposition lasted for seven months and drew more than 17 million people. The Territory of Hawaii viewed it as an important opportunity to promote its products, land, people and tourism, and the legislature appropriated over $100,000 for the event. The main attraction turned out to be the Hawaiian show featuring hulas and songs which ran many times a day. This was the first time that Hawaiian music had been so extensively promoted on the U.S. mainland and it soon swept the country, resulting in a cross-pollination of the distinctively Hawaiian sound with those of other musical styles like “Swing” jazz and Country & Western and generating in a new kind of Hawaiian music called “hapa haole.”

This fine early example of a Martin 0-18K bears serial number 14776 and has been customized with a painted pineapple motif. With its koa top, back, and sides, rosewood bindings and ebony fingerboard the instrument produced a big sound and a snap and dryness in tone that was not heard in spruce top guitars. This was important during a time when bands were getting bigger, audiences larger, amplification still quite primitive and electric instruments yet to be developed.

One interesting aspect of some 0-18Ks was an adjustment that could be made to raise the action on the strings. This allowed the guitar to be played in the usual way, or as a slack-key (open tuned) steel guitar using a small metal bar as a slide—part of the uniquely Hawaiian sound that everyone now recognizes around the world.

Roy Smeck, the "Wizard of the Strings" demonstrates his incredible ability on the lap steel guitar, ukulele and banjo.