How to tie a leader to a main line

[kickisasssebas]

https://youtu.be/ZqlVRFhs_Fg

 

[kingofbeasts]

Uni to uni knot is not the fastest (in my opinion) nor the strongest and when we talk about leader , maintaining the as much as possible the line internal resistance to traction is a key factor. Therefore, a strong knot is better then a quick knot because you never know when you hook into a PB. You can find in the link a top of best knots to tie a leader :
http://www.anglers-secrets.com/lines-and-knots/

My personal favorite remains the (improved) FG knot as a good time spent tying/ strength rapport.