Winkler Woods is a lumber company that claim to have been founded in the 1800's in Northern California. In the early 1970's they stated working as a lumber company on the Hawaiian Islands and by 2001 they had become a major international supplier of koa. In 2003 Winkler Woods LLC was actually formed and its primary business was to supply koa to luthiers worldwide. 

By 2005 they had realised, (like the Hawaiian Mahogany Co. before them), that it made sense to cut out the "middle man" as it were, and to go into production themselves, first with Big Island Ukuleles and then with Honu Ukuleles, (the ukuleles sometimes had a turtle shaped bridge). The Ukuleles themselves were actually made in Vietnam but the wood was suppose to be supplied by Winkler. 

In 2012 they brought out a third range of Ukuleles called Imua, (with an Abalone I on the headstock). This time though the instruments are actually made in a factory in Honolulu, Hawaii. The factory was set up in conjunction with Shinji Takahashi and his Seilen design company and started out only making koa Sopranos, Concerts and Tenors. It has expanded its catalogue to use other, mainly local, tonewoods, long neck variations on the scales and a host of small ukulele accessories, it still doesn't do Baritones or Minis.

Since about 2015 Winkler Woods has become part of a holding company called Jacy Inc. (Jorma Winkler is still CEO though), and all of the Vietnamese businesses have been sold off to Hosco Inc. so Imua is the only Ukulele brand left, but it does have an expanded logo to include a kind of figure 8 body shape below the I and a dot above to give a stylized Ukulele with the dot as the headstock.