The Bb tuning — introduced to me by Joe Tate at George Kahumoku’s Slack Key Guitar Workshop last June — is a unique tuning in a couple of respects. First, the tuning should be called BbMaj7 Add 9, if you want to be accurate… the string notes are F-Bb-D-F-A-C, so you have the notes in a Bb major chord in the first three strings – F-Bb-D, and the notes of the dominant chord, F, on the top three strings – F-A-C.
Even though it’s not an open tuning, it is well-suited to playing songs that use the two basic chords, Bb (I) and F7 (V7), since there are easy-to-play two fingers positions for both of these chords.
On George Winston’s Dancing Cat website, this tuning is identified as “Led’s New C Wahine Tuning” (G-C-E-G-B-D), tuned down to play in the key of Bb. Led uses this tuning when he plays Koke’e with the capo on the second fret.
This tuning, compared to most other slack key tunings, can be considered a relatively “tight” tuning, given its string intervals. It spans 19 chromatic scale steps as opposed to Taro Patch, for example, which spans 24 steps or two full octaves.
If you’ve tried this tuning, please write and let me know, and what you think of it.