European 4-1 is probably the most common weave used in maille-dom, due to its simplicity and ease of construction. It's most famous for being the weave used in European knights' armor. European 4-1 can be made using several techniques, such as one-ring-at-a-time (ORAAT), one-open-one-closed (OOOC) and others. This tutorial describes the OOOC style.
European 4-1 can be made with ARs down to around 3. The smaller the AR, the tighter the weave will be. AR's above ~5 can be tricky to use for beginners, as the rings can flip around so they're backwards of how they're supposed to be. It's usually not a problem to flip them back around though.
Metric sizes - approximately 0.5mm wire with 2mm inner diameter; 0.6mm wire with 3mm inner diameter; 0.8mm wire with 3.5mm inner diameter; 1mm wire with 4mm inner diameter, 1.5mm wire with 6.5mm inner diameter, and so on.
New rings are brass, old rings are steel.
Step 2: Close 2 rings and put them on an open ring. Pass the open ring down through the bottom right ring and up through the upper right ring from the fivelet.
Step 3: Close 2 more rings and put them on an open ring. Pass the open ring through the 2 closed rings from the previous step.
Step 4: Repeat Step 3 until the chain is the desired length.
Step 5: Close 2 rings and put them on an open ring. Pass the open ring through the 2 bottom rings from the initial fivelet.
Step 6: Close a ring and put it on an open ring. Pass the open ring through the bottom right ring from the previous step, and the next 2 rings from the chain.
Step 7: Repeat Step 6 until the chain is the desired length.