No.597 (FP&DM)

An extraordinary problem! The analysis gives an extraordinary pleasure, after revealing much more of beautiful virtual content then it is mentioned in the solutions.

Some introductory questions for the analysis.
Are the two half-idle black pieces bRb5/bBf7 added just to achieve the artificial strategic effects which are not naturally needed in the scheme? These half-functional pieces would spoil the efficiency of the mechanism.
Wouldn’t it be more natural to use the natural/intrinsic features of the scheme for an economical and perfectly efficient mechanism? There’s an idle bhLI in each phase and a possible reciprocal line obstruction might make both bhLions participating in the mechanism in both twins. That obstruction would result with a need for antipin.
Example 1 (no wK)
Pieces
white hurdlecolourchanging LIa6
black hurdlecolourchanging LIc4f5
White Ba8
Black Bc7 Rd7 Sd6 Ph5 Ke3 Pa2 Pe2 Sf2
Stipulation H#2
Twin Move a6 f8
—
a) 1.hLIf5-c8[d7=w] hLIa6-h6[d6=w] 2.hLIc8-c5[c7=w] Sd6-f5#
b) whLIa6–>f8
1.hLIc4-c8[c7=w] hLIf8-a3[d6=w] 2.hLIc8-e6[d7=w] Sd6-c4#

Next question, if bSd6 must be white in the end, why it is not white initially? It is transformed in both phases by the same whLI. The fact that whLI arrives on different squares would make a good answer, but only if that difference would not be achieved by the twinning.
It would be more convincing if whLI would change the colour of different pieces for some good reason, eg. reducing a black line to a single square where the thematic antipin will occur.
Example 2
Pieces
white hurdlecolourchanging LIh1
black hurdlecolourchanging LIc4f5
White Ba8 Sd6 Pb5 Ph5 Ka4 Pa2
Black Bc7 Rd7 Ke3 Pe2 Pf2
Stipulation H#2
Twin Move h1 a1
—
a) 1.hLIf5-c8[d7=w] hLIh1-h6[h5=b] 2.hLIc8-c5[c7=w] Sd6-f5#
b) whLIh1–>a1
1.hLIc4-c8[c7=w] hLIa1-a3[a2=b] 2.hLIc8-e6[d7=w] Sd6-c4#
This example would work also with bRB5&bBf7 and wKf1, bhLIc1h3 (-bPe2f2)=(6+7).

The obvious central point for the analysis of the published original is the static pair bBc7 & bRd7. They both will become white (passively) in both phases, so the question is why they are not white from the beginning? Of course, beeing white already on the diagram, they might cause many cooks and besides that, the whole concept with the pair of black Andernach Lions would be ruined. These two pairs of pieces mutually justify each other’s existence.
A truely original idea will offer more than mutually-justifying reasons for the elements of realization.
Is there some complex dynamics in the logic, deeper than just changing the order of ColourChange, which would show more than a trivially repeated “creation of indirect batteries” with the same, painfully static rear peaces which guard exactly the same flights?
At first glance, the content is based on a rather static logic, using too many static pieces.

But the dynamics of logic is actually marvelous, although it’s not very obvious!

It is clear from the solutions that bBc7/bRd7 are transformed in a reciprocal order, due to the different starting positions of black h-Lions and due to their final target-squares. The final line-obstructions (c5-f5/f7-c4) and antipin effects (on g5/b3), present a nice geometrical play on 3 lines by each black hLI.
This “reciprocal geometry” is motivated by the necessary transformations of bBc7/bRd7 and that motivation seemingly justifies the scheme quite enough.

Just one more question and the full beauty of the mechanism will show up.
Where is the mentioned “reciprocal geometry”? In each phase, only one bhLI plays and the other is idle, that would not make a reciprocity and the idea itself would be just an artificial play of unrelated pieces without a convincing unifying mechanism.

The idea is a masterpiece! The virtual play which shows it, is not even mentioned in the solution.
Here’s the reciprocity:
a) 1.hLIh3-c8 [d7=w] hLIa6-e6 [d6=w]?? 2.hLIc8-c4 [c7=w] Sxc4+ 3.hLIc1-c5(c6,xc7)[c4=b]!!
b) 1.hLIc1-c8 [c7=w] hLIf8-c5 [d6=w]?? 2.hLIc8-f5 [d7=w] Sxf5+ 3.hLIh3-e6(xd7)[f5=b]!!
If whLI would try to interfere thematically on the lines of bBf7/bRb5, reciprocally mixing the plans of the two phases, the respectively “idle” bhLI would prevent it!
The try-plan in a) must be changed, the same pieces will play but differently motivated because bhLIc1 MUST be made idle in a).
The try-plan of a) will be used as a real-plan in b) but now bhLIc1 will play. However, the motivations for the play of pieces will be changed because bhLIh3 must be made idle in b).
The logic sequence may continue to close the cycle.
The real-plan of b) can be tried with active play by bhLIh3 as a try-plan in a), where whLIa6-e6 is possible etc.

A simple need for ColourChange of bBc7/bRd7 is dynamically and reciprocally combined with the changing additional motivations for W1 (line-obstruction/antipin) and B2 (sacrifice/line-obstruction). This creates a fantastic logic cycle and an additional dimension to the antipin which is therefore not a “simple” strategic tool to determine the arrival square for whLI!
-In the tries, one bhLI plays but the plan fails because other bhLI would change the colour of wS which cheks bK.
-In the solutions, the bhLI which plays would alone be able to transform wS, and making the other bhLI idle would not be enough to adjust the plan. So, the same check-parrying possibility is present both in the tries and the solutions!
The very possibility of antipin is The Detail which makes a difference. The lack of that possibility in the tries causes all these changes of plans and motivations, with the possibility of antipin as the final goal. It is not just “how to determine the arrival in W1”!

I am not sure what you wanted to say. If you see the whole content without any deeper analysis, that’s indeed great. I don’t need analysis in most cases but my abilities are to low to comprehend this problem without a considerable work.
Of course, it would have been easy if in the given solution the tries had been mentioned.

At first I’ve seen a not very complex but not too simple idea with a familiar ODT, but that content was achieved in an original way – by the specific play of h-Lions.
A pretty decent idea.
But also at first, the realization looked bad, too expensive for the idea.
So, my impression without the analysis was actually not very good. The “anatomical dissection” helped me to perceive and comprehend the wonder.
I admit that the true richness of the content surpasses my abilities of instant perception.

What was your impression without the analysis?