6 Ca(OH)2 (s) + 6 Cl2 (g) → Ca(ClO3)2 (aq) + 5 CaCl2 (aq) + 6 H2O (l)
This is an oxidation-reduction (redox) reaction:
10 Cl0 + 10 e- → 10 Cl-I (reduction)
2 Cl0 - 10 e- → 2 ClV (oxidation)
Cl2 is both an oxidizing and a reducing agent (disproportionation (dismutation)).