Latest Grateful Dead resurrection -- a duo

Grateful Dead bassist Phil Lesh (L) and guitarist Bob Weir -- shown here in concert in Los Angeles in 2009 -- will hit the road as a duo in March 2018

Two founding members of the Grateful Dead on Monday announced their first-ever tour as a duo -- the latest version of the classic counterculture jam band that officially retired in 2015.

Phil Lesh, the Grateful Dead's bassist, and Bob Weir, the group's rhythm guitarist, announced six concerts for March 2018 -- two each in New York, Boston and Chicago.

The pair said that each concert would consist of two sets, one electric and one acoustic, featuring the Dead's music.

They said the touring idea emerged after Weir played at Terrapin Crossroads, a music venue Lesh has opened in northern California.

"The intuitive playing that we have developed over five decades of creating music together always leads to new realms of musical experience," Lesh said in a statement.

With their slow-jamming blues-inflected rock, the Grateful Dead emerged around hippie-era San Francisco in the 1960s to become pioneers of underground music.

Encouraging a communal experience, the band drew legions of "Deadhead" fans who would follow them from concert to concert and swap bootleg recordings.

Guitarist Jerry Garcia, the band's unofficial frontman, died in 1995. The group reunited in 2015 to play five sold-out stadium shows billed as their finale.

Nonetheless, band members including Weir have kept touring as Dead and Company, featuring younger rock guitarist John Mayer .