M9 turning 90 degrees

[Munster]

p97 "4. when  M9 turning 90^O, troops will always expand by the minimum necessary to create a legal formation. They turn into a formation that is at least as wide in BW as the old one was deep (rounded up), and then expand up to 1 BW on each side of the original to make the formation legal (9.3)."

Several questions arose, in general:

• what does 'rounded up' refer to? I'm unclear how you can have less than unitary values for ranks deep; and
  does "
• then expand up to 1 BW on each side of the original to make the formation legal" mean that it is a minimum requirement to add two files (one each side)?

The examples that brought up the question.

• Skirmishers 2 wide, 3 deep turn 90 degrees, the new formation is 3 wide and 2 deep - is this correct.
• Infantry formation 3 wide, 1 deep turns 90 degrees, is the new formation 2 wide and 2 deep (1 stand in the rear rank) the minimum according to 9.3, or 3 wide, having turned into a 1 wide column that must immediately re-deploy a stand on each side of the initial stand?

[steads]

• what does 'rounded up' refer to? I'm unclear how you can have less than unitary values for ranks deep;
  

Rounded up refers to the original depth of the unit in mm rounded up to a whole number of Base Widths (40mm's in 15mm)
So in 15mm (with 40mm Base Width) 2 files of 3 bases of mounted are 90mm deep and thus become 3 bases wide when they turn.

• then expand up to 1 BW on each side of the original to make the formation legal" mean that it is a minimum requirement to add two files (one each side)?

This is usually to deal with thin lines turning but sometimes others need it as well. The key is the "up to" so if expanding on one side is sufficient to make a legal formation then you only expand on one side: which side is the owning players choice.
Examples:

• 6 bases of Long Spear deployed in 3 files of 2 bases (in 15mm=120mm x 40mm) When turned would  become 1 wide and 6 deep which is an illegal formation (min 2 wide) and so would expand on one side to become 2 wide and probably 3 deep (but could be 2+4 or 1+5)  The owning player decides which side to expand.
• 9 bases of Light Foot deployed in 3 files of 3 bases (in 15mm=120mm x 60mm) When turned would become 2 wide with one file 4 deep and the other file 5 deep which is an illegal formation (max 4 deep) and so would expand on one side to become 3 wide and probably 3 deep (but could be 4,4,1 or 4,3,2)  Again the owning player decides which side to expand.
• 9 bases of Light Foot deployed as a screen in 9 files of 1 base (in 15mm=360mm x 20mm) When turned would become 1 wide and 9 deep which is an illegal formation (max 4 deep) and so would expand on both sides to become 3 wide and probably 3 deep (but again could be 4,4,1 or 4,3,2)  The owning player must expand one base on each side.
  

• Skirmishers 2 wide, 3 deep turn 90 degrees, the new formation is 3 wide and 2 deep - is this correct.

No, they remain 2 wide and 3 deep: In 15mm the original formation was 60mm deep which rounds up to 2BW (80mm).

• Infantry formation 3 wide, 1 deep turns 90 degrees, is the new formation 2 wide and 2 deep (1 stand in the rear rank) the minimum according to 9.3, or 3 wide, having turned into a 1 wide column that must immediately re-deploy a stand on each side of the initial stand?

The final formation is 2 wide (2+1 Deep) because you only expand the initial 1 wide column until legal.

Hope that helps
Stephen

[Munster]

Thanks, I should clarify I was referring to cavalry skirmishers, so they would move from 3 deep to 3 wide - correct?

[steads]

Yes that is correct (in 15mm: 90mm becomes 3BW (120mm))

[lionheartrjc]

Worth also noting that SUGs that advance directly ahead (M2) or with a wheel (M3) can contract/expand up to 2BW.  However they cannot do this in a Turn 90 with Move (M11). 

Always felt the turning 90 and changing frontage/depth was slightly odd for skirmishers.

Richard