diff --git a/Makefile b/Makefile
index 59e56b8..f07a95d 100644
--- a/Makefile
+++ b/Makefile
@@ -1,10 +1,15 @@
-TARGETS=$(patsubst dates/%.yaml, dates/%, $(wildcard dates/*.yaml))
+TARGETS=$(patsubst dates/%.yaml, dates/%/ALL, $(wildcard dates/*.yaml))
 ALL: ${TARGETS}
 
 clean:
 	rm -rf ${TARGETS}
 
-dates/%:
-	mkdir -p $@
-	./generate.rb $@.yaml $@
-	$(MAKE) -C $@
+# Keep Makefiles
+.SECONDARY: $(patsubst dates/%/ALL, dates/%/Makefile, $(TARGETS))
+
+dates/%/Makefile: dates/%.yaml $(wildcard decks/*.yaml)
+	mkdir -p $(shell dirname $@)
+	./generate.rb $< $(shell dirname $@)
+
+dates/%/ALL: dates/%/Makefile
+	$(MAKE) -C $(shell dirname $@) $(shell basename $@)