Half Persian 4-1 is a dang sexy weave. Getting the hang of weaving it is tricky, but it's worth it. The hardest part of weaving Half Persian 4-1, in my opinion, is getting the initial ring positions correct. You have to do some flipping, twisting, and other spatial chicanery that can throw you for a loop the first few times. Take it slow at first, and for Pete's sake, be careful if you put it down before you get a good-sized patch. In fact, once you make a stable patch, it's handy to keep it around as a 'starter chain' and build future chains off that one. It's always easier to continue Half Persian 4-1 than it is to start it from scratch.
Half Persian 4-1 takes an AR of 5 and up. You can probably make it work with high 4.x, but to have enough room to comfortably work, go with 5 or higher. 22awg 1/8", 20awg 3/16", 18swg 1/4" and 16swg 5/16" work.
Metric sizes - approximately 0.6mm wire/3mm ID; 0.8mm wire/4.8mm ID; 1.2mm wire/6.4mm ID; and 1.6mm wire/8mm ID.
New rings are gold and old rings are steel.
Step 1a: Slide the middle bottom ring to the right and the rightmost ring to the left, as if they were changing places. The leftmost bottom ring should just hang out where it is.
Step 1b: Take the middle and rightmost ring (the rings you just slid) and carefully rotate them, as if you were unscrewing them. They should end up so that what started as the rightmost ring is now in the middle, and vice versa.
Step 2: Close a ring and put it on an open ring. Pass the open ring up through the first 2 bottom rings (leftmost and middle), and down through the third bottom ring (rightmost). Make sure it doesn't go through the top ring from the previous steps.
Step 3: Close another ring and put it on an open ring. Pass the open ring through the second and third bottom ring and down through the last bottom ring. Make sure it doesn't go through any of the top rings.
Step 4: Repeat Step 3 until the chain is the desired length.
Step 5: When you reach the end of the chain, add an open ring as usual. You don't need a closed ring for this last one.