Ok, a whole bunch of ways of playing this but
I guess you should at least know how the man himself
plays it!

Its a stripped down 'G5' power chord shape to kick off
(Ritchie likes to play in 'Gm' a lot)and should ideally be
picked with 2 FINGERS (or THUMB AND FINGER) rather than with
a plectrum!  It goes like this.....(Ted Parshall pretty much
worked it out but here the opening is played at the fifth fret
with that stripped down 'G5' shape, rather than an open string
phrase on the D and G string)

e --------------------------------------------------------
B --------------------------------------------------------
G ------3---5-------3---6---5--------3----5----3----------
D --5---3---5---5---3---6---5----5---3----5----3----5-----     .....REPEAT
A --5-----------5----------------5------------------5-----
E --------------------------------------------------------


Other chords..........

This bit drives along the verses 'We all came out to Montreaux....' etc.)

e -----------------
B -----------------
G -----------------
D --5---3---5---5--     .....REPEAT (DONT power chord this! pick the notes e.g
A --5---3---5---5-- 'We all came out to Montreaux on the Lake Geneva shoreline'
E --3---1---3---3--  3,5,5 x 5 ..............................1,3,3,3,5,5,3,5,5
   play
   this
    'G5'
   power
   chord
    x5
   times

Little change up at the 'Smoke on the water, fire in the sky....' bit....


e ----------------------------------------
B ----------------------------------------     Mix this up between picked notes
G --5-------------3----------5------------     and punched power chords to get
D --5---6----5----3----5-----5-----6------     a really nice feel to how this
A --3---6----5----1----5-----3-----6------     section gets back to the original
E ------4----3---------3-----------4------     riff at the top

Ritchie Blackmore - probably the most overlooked guitar hero of all
time in this world of shred (yawn)