The common method used to place the marking lines on a C10 division uses the concept of setting each pair of opposite pins as a set of N/S poles. This concept is a good visual one especially when learning, but there is an alternate method that many people find quicker and smoother to work. The method is shown in several Japanese books; it was demo'd at a Southern Style StitchIn and shared on the TT list so it could be added here - thanks to Elsie B. and KJ W.

        Wrap a mari, place the pins for a C10 in the usual manner, and pick one pair to act as a North and South pole (temporarily). Use this set of pins and place a Simple 10 set of vertical marking lines. The remaining pins are then grouped into two sets - here they are red and green. Once you get the hang of it you need not color code the pins - this is for learning and demo purposes.
        It's important to remember as you apply the marking threads with this method to keep snug tension on the thread. Don't pull the pins off alignment, or falsely shorten distances. However, you will be looping the thread around the pins and unless you keep tension on the thread, this will add a tiny but noticeable play in the thread that will result in loose markings unless you maintain tension as you place the marking lines. It works to visualize marking the ball in three "sections" - the north pole area, the middle section/obi area and the south pole area. The red pins are around the north pole and the green pins are around the south pole. The middle area is "fenced" by the red pins and green pins.

Be sure your mari is set up similarly to this	Thread the marking thread onto your needle, do not cut off. Use it as a spool thread. Enter at Pin1, exit a small distance away.	Pull end through, tie a knot. Snug it up to the mari surface and "pop" it into the mari base to bury and anchor the knot.
Use Points A through E to trace a 5 Point Star with the marking thread.	Wrap from Point A to C to E to B to D and back to A. Remember to keep snug tension but do not distort.	You will have returned to Point A; now wrap around the perimeter of the pentagon.
Proceed to Points B, C, D, E and back to A. Remember to keep thread snug.	Begin to use the green pins centered around the South Pole and zig zag from A to 1 to B to 2 etc., back to A.	There will be another trip around the midsection of the ball, again in a zigzag pattern but a wider pattern. Go from A to 2 (rather than 1)...
2 to D (rather than C)...	continue in this pattern, and it will take two cycles around the middle of the mari to return to Point A.	When you have returned to your starting point, the NP and each red pin will have 10 spokes radiating from the center.
Turn the ball over for the South Pole. End off the thread, and re-enter it at Green Pin A.	Repeat the five point star pattern around the pole	and repeat the pentagon perimeter wrap.
End off the thread - all pins will have ten spokes radiating from them.  Do not remove pins until tacking is completed.	Tack centers of pentagons, and adjust marking lines for symmetry. The easiest way to do this is locate the diamonds formed by adjacent pentagons and focus on "evening" them for size and symmetry - doing so will adjust the pentagons into even and symmetrical shapes.	Tack intersections, remove pins. All set!