4 files changed, 22 insertions, 6 deletions

diff --git a/blue.asm b/blue.asm
index abbd4b0f..fe2d9452 100644
--- a/blue.asm
+++ b/blue.asm
@@ -1,2 +1 @@
 _BLUE EQU 1
-_RED  EQU 0
diff --git a/constants.asm b/constants.asm
index 3496aa6a..85990c48 100644
--- a/constants.asm
+++ b/constants.asm
@@ -1,6 +1,4 @@
-_JAPAN EQU 0
-_GREEN EQU 0
-_YELLOW EQU 0
+INCLUDE "version.asm"
 
 INCLUDE "macros.asm"
 
diff --git a/red.asm b/red.asm
index 882bf66a..571f24e0 100644
--- a/red.asm
+++ b/red.asm
@@ -1,2 +1 @@
-_RED  EQU 1
-_BLUE EQU 0
+_RED EQU 1
diff --git a/version.asm b/version.asm
new file mode 100644
index 00000000..6f80aa1c
--- /dev/null
+++ b/version.asm
@@ -0,0 +1,20 @@
+if !def(_RED)
+_RED    EQU 0
+endc
+
+if !def(_BLUE)
+_BLUE   EQU 0
+endc
+
+if !def(_JAPAN)
+_JAPAN  EQU 0
+endc
+
+if !def(_GREEN)
+_GREEN  EQU 0
+endc
+
+if !def(_YELLOW)
+_YELLOW EQU 0
+endc
+