1. - Lb2?/Lc1? 2. Sa3+ Lxa3 3. Txb4+ Lxb4#
However: 1. Sa1?/Se1?/Sd4? (2. Txb4+) La3~!
That means: La3 and Sc2 are subjected to mutual remain-obligation/wechselseitige Verharrungspflicht! 

1. - hxg1D,L? 2. Dxe6+ Kxc5 3. Db6+ Kc4 4. Se3+! D,Lxe3
5. Txb4+. However: 1. Se3+? Kd4 2. Sc4+ hxg1D,L! 3. e3+ D,Lxe3!

Solution:

1. Lf2!! thr. (2. Se3+ Kd4 3. Sc4+ gxf2 4. e3+ Kxc4
5. Txb4+ Lxb4#)
1. - gxf2! 
Attention:
2. Sd3(!) (3. Sb2+! Lxb2 4. Sa3+ Lxa3 5. Txb4+) 
2. - Lb2! "Counterflight", Umnow II (3. Sb2?? 3. Sa3+? Lxa3 4. - Lxb4+ 5. Sxb4...)
Finale furioso:
3. c8D,T+! Lxc8, thematic 
4. Se5+!! Lxe5
5. Dc7+ Lxc7#
6. Lb6?? → finally the sacrificial key turns out to be a flight maneuver, too!

Thematic try: 1. Sd3? Lb2!

Non-thematic addition:
3. - Txc8
4. Dc5+! Txc5
5. Lxb5+ Txb5#

Thrilling fight between interference and not-interference, attraction and repulsion... An extraordinary bilateral challenge, unconventional in every respect.