Friday, January 29, 2010

DBA question

Given the movement sequence from panel 1 to 2, which is the correct outcome, 3 a or b?


  1. I think 3b. The left Cv doesn't have legal contact on the Ps but does on the Sp. It must turn to face and the Cv slides to confirm. I think 3a is crazy. But what do the rules say?


  2. That's what I thought, but see this thread- the key is what it means to "make room" when you turn to contact. That would suggest 3a is correct, since the Cv "makes room".

  3. my first thought was that the calvary shouldn't be able to contact the rear of the Psiloi because it didn't start it's turn entirely behind the Psiloi stand... but then realized that's HOTT I'm thinking of... (curse these similar rules...)

    How about 3c...?

    Because the Psiloi Supports the Spear against Cavalry I would assume the Psiloi would turn with the Spear to face the cavalry on the Spear's flank (in fig. 2) and the Cavalry in contact with the Psiloi's rear (in fig. 2) would then act as a flank contact against the whole mess in a single combat...?

    See Close Combat on p.10 of DBA 2.2 "If an element so contacts the flanks of two enemy elements , both these turn, the 2nd moving to behind the first...."

    Of course the line before that is "Elements not in mutual fronte edge contact with and enemy element but contacted to the flank or rear by an enemy front edge turn to face the FIRST to so contact at the end of the movement phase, the contactor making room...."

    So maybe the psiloi would have to first turn to face the cavalry to it's rear as it obviously would have to have been the first to move... so, as Bob says, 3b...?

    Getting back to my original idea however... I guess the bigger question is does the cavalry actually HAVE enough movement to execute this maneuver...? I don't really have my head around the geometry of the 15mm game - but in 25mm a base is 150 paces wide, the spear would be 50 Paces deep, the psiloi 75 paces, the cavalry would be 125 paces deep. so it would take a full 250 paces for the cavalry to clear the Spear/Psiloi, it would have to turn completely around (~180 paces) and side slip 150 paces to line up with the Psiloi, for a grand total of 580 paces... much beyond the regular 400 pace movement of cavalry...

    this makes my brain hurt...

  4. Huh, I see the logic of the yahoo post (and Beattie is a pretty big hitter in DBA). But what is "actually" happening in his interpretation?

    The Psiloi turn around (easy enough to see). But the spear, seeing the second cavalry unit, counter-charge it (instead of turning and setting their spears) and, in doing so, put themselves in a position whereby losing they would be quick killed? What kind of idiot spear commander would do that?

    Tim also raises a good point about whether the math works. I just tried this and there isn't room for the Cv (even if it is LH) to do that as far as I can tell. Moving past the Ps/Sp combo takes about 2 inches of movement. Then the crazy wheel (using the front corner) takes another 4 or so inches to get around.

    Maybe this could happen in two bounds if the foot player had a low pip roll and chose to do something else on his turn?

  5. Or possibly if the foot player moved forward (instead of turning into the cavalry, thereby missing out on a +5 v +3 fight.

  6. Movement is measured from the starting position to the end position of any base corner (pg 9), so if you measure to the front corners it's legal, at least in 15mm.

    But yeah, it's bad for the spear.

    If the side contact happens first, the spear and psiloi turn (since that was the first contact) and they are both destroyed on a recoil.

  7. Huh. I though you had to trace the movement of the corner that moves the farthest and that was the maximum move possible. The rule does say "...the maximum distance between the starting point of any base corner of a single element...and that corner's final position.."

    But just before it is there is a rule that allows a unit to ignore wheeling distances only in the case where it is trying to close the door. This exception suggests the general rule is that wheeling distance must be considered?

    Page 23 of wadbag suggests you must use a series of steps (intermediate moves) if a direct move would (among several things) require any corner of the element would need to pass through an enemy element.

    It seems to me that bringing the cavalry around to make the contact you want would require it to wheel to face assuming it cannot contract its frontage to be smaller than it is and that resulting sum of the intermediate moves would violate the move limits.

    But maybe I'm wrong. Is this some new strategy you are working out? :)

  8. You must be a biologist or something... There's a biologist that regularly plays with us and geometry seems entirely beyond him and thus he does some "funny measuring" too.

    Yes, furthest corner to furthest corner... BUT you can't go THROUGH enemy elements - which that corner you are measuring would have to do to do what you are suggesting - you have to go around them! Clear their depth, then do the corner to corner.

    You know what even WITH furthest corner to furthest corner you don't have the movement.... the furthest corner moving is the cavalry's rear left corner, no? We can figure this out with a simple trig... (A-squared + B-squared = C-Squared...) A= the width of the two bases (80mm), B= depth of cavalry (30mm) + depth of Spear (15mm) + depth of Psiloi (20mm) = depth of Cavalry again (because that's it on the other side facing in the opposite direction... 30mm) (total 95mm). Squared them, add them together, find square root, divide by 25.4 (to get inches).... I get 4.8 inches... 480 paces.... sorry Dave, it's still too far!

  9. Where does it say furthest corner? It says any corner on pg 9.

    Consider the strict interpretation of "every" corner. So a base that is very deep (e.g a warwagon) is very restricted in the way it can wheel since the rear corners geometrically must move very far? How else can a war wagon wheel 45 degrees for example?

  10. Hmmm. Perhaps "corner that moves the furthest" is a better term. It does not specify on page 9 that you have to measure the actual distance the corner moved.

    But if the direct start-to-finish corner measure would require the element to have moved through an enemy element, then it can't make the move (no provisions for interpenetrating enemy troops).

    So then you break the move into a series of parsimonious steps and measure each. Wadbag page 21.I still don't think it can make it but I'll go give it a test (no fancy math for me!).

    Is this some theoretical discussion. Or did someone do this?

  11. This is theoretical. If you treat the element like an amoeba both front corners distances are mathematically legal without crossing the enemy base.

  12. Huh, that's an interesting idea.

    I think the element must move in a fashion that reflects a constant frontal distance of 40mm (maybe page 8?).

    Base shape and size seem very important in DBA so why would that convention be temporarily suspended in single element movement?

    I wonder what the doyens on Fanaticus would make of that?

  13. I don't see the frontal distance a problem considering two parsimonious steps. If you wheel 90 degrees, the front left corner moves just over 2", as we all know. If you then slide along the back edge of the Ps, allowing it to behave like an amoeba, that same corner moves about 40mm plus a smidge since it overhangs, but the total move is less than 4".

    I reckon it boils down to convention, I think some players always measure to the front corners. But the original question was about the behaviour of the Sp...

  14. PS- I should post one of these every week!!!

  15. If two 3Kn leave a station, heading in opposite directions...

  16. The geometry and arithmetic of these problems is trivial, it's the English (written versus intended) and convention that's always the problem.

    The 3Kn elements coincide in Rpi/V hours on the exact other side of the planet, where R gives the planetary radius, V gives the mean Kn velocity, and pi can be approximated by 22/7. But the English 3Kn is considered to get there first because it has better command structure...

  17. On reflection, I think I am wrong about this any corner business according to how most play it (except Mark and his dune-buggy warwagons). "Farthest corner" is a common interpretation (e.g. WADBAG; but why didn't Barker write "each" or "every" corner which is more explicit?) and front corner was how 2.1 described it. So under 2.2 the Cv would have to start a bit closer to make the rear contact, or a LH makes it.

  18. Now maybe I am not so crazy, the WADBAG conventions ( for DBA 2.2 state measurement to the front corners on page 2. But the WADBAG guide says farthest corner. Same group, different conventions in different pdfs. Go figure.