Sweep picking is like strumming a chord, except you want to accentuate each note in the “strum” . What you are actually going to do is pick several different notes in succession on adjacent strings with a very very slight pause in between notes. When switching strings in the direction of low to high you always pick the string down, when switching from high to low you always pick up. Using this motion it allows you to play notes much faster than if you were to alternate pick. The catch though, is you must have great coordination between both hands. As your picking hand moves up and down the strings, your fretting had has to be quick enough to keep up.

Forget trying to explain it using words, lets watch Paul Gilbert show us how in this video:

The reason I have been practicing Alexi Laiho licks is he is not the worlds greatest sweep picker. As a result his riff are somewhat simple compared to someone like John Petrucci. Although the following riff is not from Alexi, it is a common exercise for learning and practicing sweep picking.

E||------------------12--15p--12----------------------|
B||--------------13---------------13------------------|
G||----------12-----------------------12--------------|
D||------14-------------------------------14----------|
A||--15---------------------------------------15------|
E||-----------------------------------------------12--|

----------------------12--16p--12------------------|
------------------12---------------12--------------|
--------------13-----------------------13----------|
----------14-------------------------------14------|
------14---------------------------------------14--|
--12-----------------------------------------------|

--------------------------14--18p--14--------------|
----------------------14---------------14----------|
------------------15-----------------------15------|
--------------16-------------------------------16--|
----------16---------------------------------------|
--12--14-------------------------------------------|

------------------------------16--20p--16----------|
--------------------------16---------------16------|
----------------------17-----------------------17--|
------------------18-------------------------------|
--16----------18-----------------------------------|
------14--16---------------------------------------|

--------------|-----||
--------------|-----||
--------------|-----||
--18----------|-----||
------18------|-----||
----------16--|-----||

Download the tab for this riff for Guitar Pro 5.

The following riff is from Children of Bodom’s Towards Dead End off of 1999’s Hatebreeder. This is the intro riff as well as the chorus. I have just posted the sweep picking parts that I use to practice the technique.

----------17--22p--17--------------17--22p--17------|
------18---------------18------18---------------18--|
--19-----------------------19-----------------------|
----------------------------------------------------|
----------------------------------------------------|
----------------------------------------------------|

----------17--22p--17--------------17--22p--17------|
------18---------------18------18---------------18--|
--19-----------------------19-----------------------|
----------------------------------------------------|
----------------------------------------------------|
----------------------------------------------------|

----------12--17p--12--------------12--17p--12------|
------13---------------13------13---------------13--|
--14-----------------------14-----------------------|
----------------------------------------------------|
----------------------------------------------------|
----------------------------------------------------|

----------12--17p--12--------------12--17p--12------|
------13---------------13------13---------------13--|
--14-----------------------14-----------------------|
----------------------------------------------------|
----------------------------------------------------|
----------------------------------------------------|

----------12--17p--12--------------12--17p--12------|
------15---------------15------15---------------15--|
--14-----------------------14-----------------------|
----------------------------------------------------|
----------------------------------------------------|
----------------------------------------------------|

----------12--15p--12--15--18--17--15--------------|
------14-------------------------------18--17--15--|
--14-----------------------------------------------|
---------------------------------------------------|
---------------------------------------------------|
---------------------------------------------------|

Download the tab for this riff for Guitar Pro 5 now.

The following is the start of the solo from the song Children of Bodom which is also from the album Hatebreeder. It just shows how sweep picking can be incorporated into a solo. The sweep picking part starts on the 4th bar below and can be found at 3:03 in the song.

E||--------------------------------------------|
B||--------------------------------------------|
G||--------------------------------------------|
D||--10--9--7------------12--10--9-------------|
A||------------10--9--7-------------12--10--9--|
E||--------------------------------------------|

---------------------------|
--15b--------17b----18b----|
---------------------------|
---------------------------|
---------------------------|
---------------------------|

--19--17--15--------------15--14--12--------------|
--------------19--17--15--------------15--13--12--|
--------------------------------------------------|
--------------------------------------------------|
--------------------------------------------------|
--------------------------------------------------|

------------------12--15--------------------------|
--------------13----------15----------------------|
--12------12------------------16--------------16--|
------14--------------------------17------17------|
--------------------------------------17----------|
--------------------------------------------------|

------------------14--17S--19p--15-------------------||
--------------15--------------------17---------------||
----------14----------------------------16-----------||
------16------------------------------------17S--14--||
--17-------------------------------------------------||
-----------------------------------------------------||

Download the sweep picking riff from Children of Bodom solo for Guitar Pro 5 now.

So that is my little sweep picking lesson. It is not a technique that comes easily. It takes a lot of practice and you really have to focus on timing when practicing it so that when you build up speed everything is coordinated.