Mississippi-born guitar phenom Super Chikan has been making vital, unorthodox blues since the late ‘90s, when he recorded a series of stripped-down country blues rambles for the iconoclastic Oxford, Miss.-based Fat Possum label. Meanwhile, steadfast Okie Watermelon Slim has distinguished himself as a journeyman instrumentalist who honed his distinctive slide guitar style performing with the likes of Canned Heat’s Henry Vestine and piano legend Champion Jack Dupree. The two have collaborated to produce Okiesippi Blues, a wondrously laid-back collaboration that emanates the congenial good vibes and relaxed atmosphere of a late-night picking party. In an era when young blues musicians strain to attain authenticity by donning period costumes, Super Chikan and Watermelon Slim manage to make genuine American roots music simply by being themselves. They write raucous, gleefully irreverent originals like “Northwest Regional Medical Center Blues” and sound equally at home cutting loose on a distortion drenched diddley-bow improvisation as they do performing a delicate duet on thumb pianos.