Edge template IV1d

R5 C9 Sa1 Sb1 Sc1 Sd1 Sh1 Si1 Si2 Sa2 Sb2 Sc2 Vd2 Sa3 Sb3 Sa4

This template has first been mentionned by Mike Amling on David King's Hex template page

Template reductions
R5 C9 Sa1 Sb1 Sc1 Sd1 Sh1 Si1 Si2 Sa2 Sb2 Sc2 Vd2 Sa3 Sb3 Pc3 Pd3 Sa4    Vc4 Pb5 Pc5

R5 C9 Sa1 Sb1 Sc1 Sd1 Sh1 Si1 Si2 Sa2 Sb2 Sc2 Vd2 Pe2 Sa3 Sb3    Pd3 Ve3 Pf3 Sa4        Pd4 Pe4 Pf4 Pc5 Pd5 Pe5 Pf5

R5 C9 Sa1 Sb1 Sc1 Sd1 Sh1 Si1 Si2 Sa2 Sb2 Sc2 Vd2 Sa3 Sb3 Pc3 Vd3 Pe3 Sa4 Pb4 Pc4 Pd4 Pe4 Pa5 Pb5    Pd5 Pe5

There is one place that is covered by all template reductions. The only chance for Blue to prevent Red from connecting to bottom is to play in this area.

R5 C9 Sa1 Sb1 Sc1 Sd1 Sh1 Si1 Si2 Sa2 Sb2 Sc2 Vd2 Sa3 Sb3    Hd3 Sa4

Development of the remaining case
R5 C9 Sa1 Sb1 Sc1 Sd1 Sh1 Si1 Si2 Sa2 Sb2 Sc2 Vd2 Sa3 Sb3 V1c3 Hd3 Sa4    V3c4 H2b5 H4c5

R5 C9 Sa1 Sb1 Sc1 Sd1 Sh1 Si1 Si2 Sa2 Sb2 Sc2 Vd2 Sa3 Sb3 Vc3 Hd3    V5f3 Sa4    Vc4 Hb5 Hc5

More Reductions
Let's study this position with template reductions:

R5 C9 Sa1 Sb1 Sc1 Sd1 Sh1 Si1 Sa2 Sb2 Sc2 Vd2 Si2 Sa3 Sb3 Vc3 Hd3    Vf3 Pg3 Sa4    Vc4    V1e4 Pf4 Pg4 Hb5 Hc5    Pe5 Pf5 Pg5

R5 C9 Sa1 Sb1 Sc1 Sd1 Sh1 Si1 Sa2 Sb2 Sc2 Vd2    Si2 Sa3 Sb3 Vc3 Hd3    Vf3 Sa4    Vc4    V1e4 Hb5 Hc5 Pd5 Pe5

First Attempt for Blue
R5 C9 Sa1 Sb1 Sc1 Sd1 Sh1 Si1 Sa2 Sb2 Sc2 Vd2      Si2 Sa3 Sb3 Vc3 Hd3    Vf3 Sa4    Vc4 V2d4        V4g4 Hb5 Hc5 H3d5 H1e5

Second Attempt for Blue
R5 C9 Sa1 Sb1 Sc1 Sd1              Sh1 Si1 Sa2 Sb2 Sc2 Vd2      V4g2        Si2 Sa3 Sb3 Vc3 Hd3    Vf3 Sa4    Vc4 V2d4 H1e4 Hb5 Hc5 H3d5 Leading to edge template IV2b