Thematic try:
1. La5? self-blocus (2. Dxb3+ Lxb3#) Sb6+! 2. Lxb6, and threat (3. La5, return) is being parried. 

Motto: slower speed...

1. Lb4! (2. Sd6+ Kd4 3. Sc8+ Kc4 4. Sb6+! axb6 5. Dxb3+)
1. - Dg8, Dh8 looks good, however: 2. Sd6+ 3. Sc8+
3. - Dxd8, guarding a5... 4. Lc3+, return! Kc4 5. Dxb3+
Therefore:
1. - Sc7! 
2. La5! Sd5 instead of - Sb6+ (3. - Kd4!)
3. Txh4+(!) Dxh4
4. Se5+! Kd4
5. Da1+! Sxa1# 6. Kb4?? 6. Tb3??!
3. - Kxd3 4. Sc5+ Sxc5#
3. - Sf4 4. Dxb3+ Lxb3#

Step by step-decoy of knight a8 to the middle of the board results in unsuspected discovered mate. Lively full-length first threat; Roman replacement-defense, covertly motivated turbulent rook-sacrifice, motive inversions, etc.  

Schrittweise Gängelung des Sa8 zur Brettmitte führt zu unvorhersehbarem Abzugmatt. Vollzügig-spritzige Erstdrohung; Römische Ersatzverteidigung, versteckt motiviertes turbulentes Turmopfer, Motivinversionen, etc.