Unusual way of a draw

Red to play and draw, this time by successfully getting the opponent under lock and key!

Red 8 pieces, Black 12 pieces.

1. R3=5 ch       G4+5
2. R7=5 ch       K5+1
3. C1=5 ch       B5+7
4. C5-5 ch       B7-5
5. B5-3 ch       B5-7
6. B3+5 ch       B7+5
7. B5+3 ch       B5+7
8. B3-5 ch       B7-5
9. B5+7 ch       B5+7
10.B7-5 ch       B7-5
11.B5-7 ch       B5+3
12.C5=8 (draw)