diff --git a/Z4c/interface.ccl b/Z4c/interface.ccl
index a1c633a2..0df6a038 100644
--- a/Z4c/interface.ccl
+++ b/Z4c/interface.ccl
@@ -50,3 +50,52 @@ CCTK_REAL Gam_tilde_rhs TYPE=gf TAGS='parities={-1 +1 +1   +1 -1 +1   +1 +1 -1}
 CCTK_REAL Theta_rhs TYPE=gf TAGS='checkpoint="no"' "Theta"
 CCTK_REAL alphaG_rhs TYPE=gf TAGS='checkpoint="no"' "alpha"
 CCTK_REAL betaG_rhs TYPE=gf TAGS='parities={-1 +1 +1   +1 -1 +1   +1 +1 -1} checkpoint="no"' { betaGx_rhs betaGy_rhs betaGz_rhs } "beta"
+
+
+
+# for subcycling
+
+CCTK_REAL chi_old TYPE=gf TAGS='checkpoint="no"' "chi"
+CCTK_REAL gamma_tilde_old TYPE=gf TAGS='parities={+1 +1 +1   -1 -1 +1   -1 +1 -1   +1 +1 +1   +1 -1 -1   +1 +1 +1} checkpoint="no"' { gammatxx_old gammatxy_old gammatxz_old gammatyy_old gammatyz_old gammatzz_old } "gamma-tilde"
+CCTK_REAL K_hat_old TYPE=gf TAGS='checkpoint="no"' { Kh_old } "K-hat"
+CCTK_REAL A_tilde_old TYPE=gf TAGS='parities={+1 +1 +1   -1 -1 +1   -1 +1 -1   +1 +1 +1   +1 -1 -1   +1 +1 +1} checkpoint="no"' { Atxx_old Atxy_old Atxz_old Atyy_old Atyz_old Atzz_old } "A-tilde"
+CCTK_REAL Gam_tilde_old TYPE=gf TAGS='parities={-1 +1 +1   +1 -1 +1   +1 +1 -1} checkpoint="no"' { Gamtx_old Gamty_old Gamtz_old } "Gamma-tilde"
+CCTK_REAL Theta_old TYPE=gf TAGS='checkpoint="no"' "Theta"
+CCTK_REAL alphaG_old TYPE=gf TAGS='checkpoint="no"' "alpha"
+CCTK_REAL betaG_old TYPE=gf TAGS='parities={-1 +1 +1   +1 -1 +1   +1 +1 -1} checkpoint="no"' { betaGx_old betaGy_old betaGz_old } "beta"
+
+CCTK_REAL chi_k1 TYPE=gf TAGS='checkpoint="no"' "chi"
+CCTK_REAL gamma_tilde_k1 TYPE=gf TAGS='parities={+1 +1 +1   -1 -1 +1   -1 +1 -1   +1 +1 +1   +1 -1 -1   +1 +1 +1} checkpoint="no"' { gammatxx_k1 gammatxy_k1 gammatxz_k1 gammatyy_k1 gammatyz_k1 gammatzz_k1 } "gamma-tilde"
+CCTK_REAL K_hat_k1 TYPE=gf TAGS='checkpoint="no"' { Kh_k1 } "K-hat"
+CCTK_REAL A_tilde_k1 TYPE=gf TAGS='parities={+1 +1 +1   -1 -1 +1   -1 +1 -1   +1 +1 +1   +1 -1 -1   +1 +1 +1} checkpoint="no"' { Atxx_k1 Atxy_k1 Atxz_k1 Atyy_k1 Atyz_k1 Atzz_k1 } "A-tilde"
+CCTK_REAL Gam_tilde_k1 TYPE=gf TAGS='parities={-1 +1 +1   +1 -1 +1   +1 +1 -1} checkpoint="no"' { Gamtx_k1 Gamty_k1 Gamtz_k1 } "Gamma-tilde"
+CCTK_REAL Theta_k1 TYPE=gf TAGS='checkpoint="no"' "Theta"
+CCTK_REAL alphaG_k1 TYPE=gf TAGS='checkpoint="no"' "alpha"
+CCTK_REAL betaG_k1 TYPE=gf TAGS='parities={-1 +1 +1   +1 -1 +1   +1 +1 -1} checkpoint="no"' { betaGx_k1 betaGy_k1 betaGz_k1 } "beta"
+
+CCTK_REAL chi_k2 TYPE=gf TAGS='checkpoint="no"' "chi"
+CCTK_REAL gamma_tilde_k2 TYPE=gf TAGS='parities={+1 +1 +1   -1 -1 +1   -1 +1 -1   +1 +1 +1   +1 -1 -1   +1 +1 +1} checkpoint="no"' { gammatxx_k2 gammatxy_k2 gammatxz_k2 gammatyy_k2 gammatyz_k2 gammatzz_k2 } "gamma-tilde"
+CCTK_REAL K_hat_k2 TYPE=gf TAGS='checkpoint="no"' { Kh_k2 } "K-hat"
+CCTK_REAL A_tilde_k2 TYPE=gf TAGS='parities={+1 +1 +1   -1 -1 +1   -1 +1 -1   +1 +1 +1   +1 -1 -1   +1 +1 +1} checkpoint="no"' { Atxx_k2 Atxy_k2 Atxz_k2 Atyy_k2 Atyz_k2 Atzz_k2 } "A-tilde"
+CCTK_REAL Gam_tilde_k2 TYPE=gf TAGS='parities={-1 +1 +1   +1 -1 +1   +1 +1 -1} checkpoint="no"' { Gamtx_k2 Gamty_k2 Gamtz_k2 } "Gamma-tilde"
+CCTK_REAL Theta_k2 TYPE=gf TAGS='checkpoint="no"' "Theta"
+CCTK_REAL alphaG_k2 TYPE=gf TAGS='checkpoint="no"' "alpha"
+CCTK_REAL betaG_k2 TYPE=gf TAGS='parities={-1 +1 +1   +1 -1 +1   +1 +1 -1} checkpoint="no"' { betaGx_k2 betaGy_k2 betaGz_k2 } "beta"
+
+CCTK_REAL chi_k3 TYPE=gf TAGS='checkpoint="no"' "chi"
+CCTK_REAL gamma_tilde_k3 TYPE=gf TAGS='parities={+1 +1 +1   -1 -1 +1   -1 +1 -1   +1 +1 +1   +1 -1 -1   +1 +1 +1} checkpoint="no"' { gammatxx_k3 gammatxy_k3 gammatxz_k3 gammatyy_k3 gammatyz_k3 gammatzz_k3 } "gamma-tilde"
+CCTK_REAL K_hat_k3 TYPE=gf TAGS='checkpoint="no"' { Kh_k3 } "K-hat"
+CCTK_REAL A_tilde_k3 TYPE=gf TAGS='parities={+1 +1 +1   -1 -1 +1   -1 +1 -1   +1 +1 +1   +1 -1 -1   +1 +1 +1} checkpoint="no"' { Atxx_k3 Atxy_k3 Atxz_k3 Atyy_k3 Atyz_k3 Atzz_k3 } "A-tilde"
+CCTK_REAL Gam_tilde_k3 TYPE=gf TAGS='parities={-1 +1 +1   +1 -1 +1   +1 +1 -1} checkpoint="no"' { Gamtx_k3 Gamty_k3 Gamtz_k3 } "Gamma-tilde"
+CCTK_REAL Theta_k3 TYPE=gf TAGS='checkpoint="no"' "Theta"
+CCTK_REAL alphaG_k3 TYPE=gf TAGS='checkpoint="no"' "alpha"
+CCTK_REAL betaG_k3 TYPE=gf TAGS='parities={-1 +1 +1   +1 -1 +1   +1 +1 -1} checkpoint="no"' { betaGx_k3 betaGy_k3 betaGz_k3 } "beta"
+
+CCTK_REAL chi_k4 TYPE=gf TAGS='checkpoint="no"' "chi"
+CCTK_REAL gamma_tilde_k4 TYPE=gf TAGS='parities={+1 +1 +1   -1 -1 +1   -1 +1 -1   +1 +1 +1   +1 -1 -1   +1 +1 +1} checkpoint="no"' { gammatxx_k4 gammatxy_k4 gammatxz_k4 gammatyy_k4 gammatyz_k4 gammatzz_k4 } "gamma-tilde"
+CCTK_REAL K_hat_k4 TYPE=gf TAGS='checkpoint="no"' { Kh_k4 } "K-hat"
+CCTK_REAL A_tilde_k4 TYPE=gf TAGS='parities={+1 +1 +1   -1 -1 +1   -1 +1 -1   +1 +1 +1   +1 -1 -1   +1 +1 +1} checkpoint="no"' { Atxx_k4 Atxy_k4 Atxz_k4 Atyy_k4 Atyz_k4 Atzz_k4 } "A-tilde"
+CCTK_REAL Gam_tilde_k4 TYPE=gf TAGS='parities={-1 +1 +1   +1 -1 +1   +1 +1 -1} checkpoint="no"' { Gamtx_k4 Gamty_k4 Gamtz_k4 } "Gamma-tilde"
+CCTK_REAL Theta_k4 TYPE=gf TAGS='checkpoint="no"' "Theta"
+CCTK_REAL alphaG_k4 TYPE=gf TAGS='checkpoint="no"' "alpha"
+CCTK_REAL betaG_k4 TYPE=gf TAGS='parities={-1 +1 +1   +1 -1 +1   +1 +1 -1} checkpoint="no"' { betaGx_k4 betaGy_k4 betaGz_k4 } "beta"
diff --git a/Z4c/param.ccl b/Z4c/param.ccl
index 849de638..36b1a8e6 100644
--- a/Z4c/param.ccl
+++ b/Z4c/param.ccl
@@ -101,3 +101,7 @@ CCTK_INT n_betaG "n power of outgoing boundary r^n fall off rate for beta"
 {
   0:2           :: "1 is my guess"
 } 1
+
+SHARES: Driver
+
+USES BOOLEAN use_subcycling_wip
diff --git a/Z4c/schedule.ccl b/Z4c/schedule.ccl
index 84a2d90e..d18ea616 100644
--- a/Z4c/schedule.ccl
+++ b/Z4c/schedule.ccl
@@ -23,6 +23,53 @@ STORAGE: Theta_rhs
 STORAGE: alphaG_rhs
 STORAGE: betaG_rhs
 
+if(use_subcycling_wip) {
+  STORAGE: chi_old
+  STORAGE: gamma_tilde_old
+  STORAGE: K_hat_old
+  STORAGE: A_tilde_old
+  STORAGE: Gam_tilde_old
+  STORAGE: Theta_old
+  STORAGE: alphaG_old
+  STORAGE: betaG_old
+
+  STORAGE: chi_k1
+  STORAGE: gamma_tilde_k1
+  STORAGE: K_hat_k1
+  STORAGE: A_tilde_k1
+  STORAGE: Gam_tilde_k1
+  STORAGE: Theta_k1
+  STORAGE: alphaG_k1
+  STORAGE: betaG_k1
+
+  STORAGE: chi_k2
+  STORAGE: gamma_tilde_k2
+  STORAGE: K_hat_k2
+  STORAGE: A_tilde_k2
+  STORAGE: Gam_tilde_k2
+  STORAGE: Theta_k2
+  STORAGE: alphaG_k2
+  STORAGE: betaG_k2
+
+  STORAGE: chi_k3
+  STORAGE: gamma_tilde_k3
+  STORAGE: K_hat_k3
+  STORAGE: A_tilde_k3
+  STORAGE: Gam_tilde_k3
+  STORAGE: Theta_k3
+  STORAGE: alphaG_k3
+  STORAGE: betaG_k3
+
+  STORAGE: chi_k4
+  STORAGE: gamma_tilde_k4
+  STORAGE: K_hat_k4
+  STORAGE: A_tilde_k4
+  STORAGE: Gam_tilde_k4
+  STORAGE: Theta_k4
+  STORAGE: alphaG_k4
+  STORAGE: betaG_k4
+}
+
 
 
 ################################################################################