diff --git a/make/py-check.mk b/make/py-check.mk
new file mode 100644
index 00000000..05687d7c
--- /dev/null
+++ b/make/py-check.mk
@@ -0,0 +1,89 @@
+.PHONY: \
+	all \
+	check \
+	format \
+	check-syntax \
+	check-format \
+	py-check \
+	py-check-syntax \
+	py-check-format \
+	py-format \
+	py-format-assignments \
+	py-check-annotation-imports \
+	py-format-annotation-imports \
+	clean \
+	clean.py-check
+
+ifndef PY_CHECK_ROOTS
+  PY_CHECK_ROOTS             = .
+endif
+
+ifndef PY_CHECK_MYPY
+  PY_CHECK_MYPY             := mypy
+endif
+
+ifndef PY_CHECK_RUFF
+  PY_CHECK_RUFF             := $(shell which ruff 2>/dev/null)
+  ifneq ($(PY_CHECK_RUFF),)
+    PY_CHECK_RUFF           += --config $(TOPDIR)/pyproject.toml
+  endif
+endif
+
+ifndef PY_CHECK_YAPF
+  PY_CHECK_YAPF             := $(firstword $(wildcard /usr/bin/yapf /usr/bin/yapf3))
+endif
+
+ifndef PY_CHECK_PYRIGHT
+  PY_CHECK_PYRIGHT          := $(shell which pyright 2>/dev/null)
+  TD_GENERATE_FILES         += pyrightconfig.json
+endif
+
+all:
+check: py-check
+format: py-format
+check-syntax: py-check-syntax
+check-format: py-check-format
+
+py-check: py-check-syntax py-check-format
+
+py-check-syntax:
+ifneq ($(PY_CHECK_RUFF),)
+	$(PY_CHECK_RUFF) check $(addprefix --exclude ,$(PY_CHECK_EXCLUDE)) $(PY_CHECK_ROOTS)
+endif
+	$(PY_CHECK_MYPY) $(addprefix --exclude ,$(PY_CHECK_EXCLUDE)) $(PY_CHECK_ROOTS)
+ifneq ($(PY_CHECK_PYRIGHT),)
+	$(PY_CHECK_PYRIGHT) $(PY_CHECK_ROOTS)
+endif
+
+py-check-format:
+ifneq ($(PY_CHECK_YAPF),)
+	$(PY_CHECK_YAPF) --diff --recursive $(PY_CHECK_ROOTS)
+endif
+
+py-format:
+	find . -type f -name '*.py' -print0 | \
+		xargs -0 sed -i -E '1{/^# -\*- coding: utf-8 -\*-$$/{:a;N;/\n[[:space:]]*$$/ba;s/^# -\*- coding: utf-8 -\*-\n([[:space:]]*\n)*/ /;s/^ //}}'
+ifneq ($(PY_CHECK_YAPF),)
+	$(PY_CHECK_YAPF) --in-place --recursive $(PY_CHECK_ROOTS)
+endif
+
+py-format-assignments:
+	find $(PY_CHECK_ROOTS) \
+	  -path './.git' -prune -o \
+	  -type f -name '*.py' \
+	  -execdir /usr/bin/sed -i 's/^\(\s\+[a-zA-Z0-9_]\+\)=\([^,[:space:]]\+\)\([,(]\)*\s*$$/\1 = \2\3/g' {} '+'
+	git diff --exit-code
+
+py-check-annotation-imports:
+ifneq ($(PY_CHECK_RUFF),)
+	$(PY_CHECK_RUFF) check --select TC,FA --diff --unsafe-fixes $(PY_CHECK_ROOTS)
+endif
+
+py-format-annotation-imports:
+ifneq ($(PY_CHECK_RUFF),)
+	$(PY_CHECK_RUFF) check --select TC,FA --fix --unsafe-fixes $(PY_CHECK_ROOTS)
+endif
+
+clean: clean.py-check
+clean.py-check:
+	rm -rf .mypy_cache .ruff_cache .pytest_cache
diff --git a/make/py-defs.mk b/make/py-defs.mk
index de6da233..a947ef26 100644
--- a/make/py-defs.mk
+++ b/make/py-defs.mk
@@ -19,8 +19,6 @@ else
   PY_SITE_PACKAGES_PATH     := $(shell $(PYTHON) -c "import site; print([d for d in site.getsitepackages() if d.find('/local/') == -1][0])")
 endif
 
-PY_MYPY                     ?= mypy --ignore-missing-imports --no-namespace-packages
-
 PY_SRC_PY                   ?= $(wildcard *.py)
 PY_ALL_PY                    = $(PY_SRC_PY)
 
diff --git a/make/py-rules.mk b/make/py-rules.mk
index ce6f16a3..acf463ff 100644
--- a/make/py-rules.mk
+++ b/make/py-rules.mk
@@ -29,8 +29,7 @@ $(PY_INSTALL_DIR_PY)/%.pyc: %.pyc
 endif
 	$(INSTALL) -p -m $(PYMODMODE) -o $(PYMODOWNER) -g $(PYMODGROUP) $< $@
 
-check:
-	$(PY_MYPY) $(shell /bin/bash $(JWB_SCRIPT_DIR)/scm.sh ls-files | grep '\.py$$')
+include $(JWBDIR)/make/py-check.mk
 
 $(PY_INSTALL_DIR_PY)/py.typed: py.typed
 	$(INSTALL) -p -m $(PYMODMODE) -o $(PYMODOWNER) -g $(PYMODGROUP) $< $@
diff --git a/make/py-topdir.mk b/make/py-topdir.mk
index 65f170f3..c6b0f3ac 100644
--- a/make/py-topdir.mk
+++ b/make/py-topdir.mk
@@ -11,71 +11,9 @@ ifndef PY_CHECK_ROOTS
   PY_CHECK_ROOTS             = $(wildcard $(TOPDIR)/src $(TOPDIR)/tools)
 endif
 
-ifndef PY_CHECK_RUFF
-  PY_CHECK_RUFF             := $(shell which ruff 2>/dev/null)
-  ifneq ($(PY_CHECK_RUFF),)
-    PY_CHECK_RUFF           += --config pyproject.toml
-  endif
-endif
-
-ifndef PY_CHECK_YAPF
-  PY_CHECK_YAPF             := $(firstword $(wildcard /usr/bin/yapf /usr/bin/yapf3))
-endif
-
-ifndef PY_CHECK_PYRIGHT
-  PY_CHECK_PYRIGHT          := $(shell which pyright 2>/dev/null)
-  TD_GENERATE_FILES         += pyrightconfig.json
-endif
-
 all:
-
-format: py-format
-check-syntax: py-check-syntax
-check-format: py-check-format
-
-py-check: py-check-syntax py-check-format
-py-check-syntax:
-ifneq ($(PY_CHECK_RUFF),)
-	$(PY_CHECK_RUFF) check $(addprefix --exclude ,$(PY_CHECK_EXCLUDE)) $(PY_CHECK_ROOTS)
-endif
-	mypy $(addprefix --exclude ,$(PY_CHECK_EXCLUDE)) $(PY_CHECK_ROOTS)
-ifneq ($(PY_CHECK_PYRIGHT),)
-	pyright $(PY_CHECK_ROOTS)
-endif
-
-py-check-format:
-ifneq ($(PY_CHECK_YAPF),)
-	$(PY_CHECK_YAPF) --diff --recursive $(PY_CHECK_ROOTS)
-endif
-
-py-format:
-	find . -type f -name '*.py' -print0 | \
-		xargs -0 sed -i -E '1{/^# -\*- coding: utf-8 -\*-$$/{:a;N;/\n[[:space:]]*$$/ba;s/^# -\*- coding: utf-8 -\*-\n([[:space:]]*\n)*/ /;s/^ //}}'
-ifneq ($(PY_CHECK_YAPF),)
-	$(PY_CHECK_YAPF) --in-place --recursive $(PY_CHECK_ROOTS)
-endif
-
-py-format-assignments:
-	find $(PY_CHECK_ROOTS) \
-	  -path './.git' -prune -o \
-	  -type f -name '*.py' \
-	  -execdir /usr/bin/sed -i 's/^\(\s\+[a-zA-Z0-9_]\+\)=\([^,[:space:]]\+\)\([,(]\)*\s*$$/\1 = \2\3/g' {} '+'
-	git diff --exit-code
-
-py-check-annotation-imports:
-ifneq ($(PY_CHECK_RUFF),)
-	$(PY_CHECK_RUFF) check --select TC,FA --diff --unsafe-fixes $(PY_CHECK_ROOTS)
-endif
-
-py-format-annotation-imports:
-ifneq ($(PY_CHECK_RUFF),)
-	$(PY_CHECK_RUFF) check --select TC,FA --fix --unsafe-fixes $(PY_CHECK_ROOTS)
-endif
-
 clean: clean.topdir
 clean.topdir: clean.py-check
-clean.py-check:
-	rm -rf .mypy_cache .ruff_cache .pytest_cache
 
 pyproject.toml:
 	$(PYTHON) $(JWB_SCRIPT_DIR)/jw-pkg.py -p $(PROJECTS_DIR) -t $(TOPDIR) --topdir-format unaltered projects create-file --format tmpl \
@@ -86,3 +24,5 @@ pyrightconfig.json:
 	$(PYTHON) $(JWB_SCRIPT_DIR)/jw-pkg.py -p $(PROJECTS_DIR) -t $(TOPDIR) --topdir-format unaltered projects create-file --format pyright \
 		--field base=$(JW_PKG_CONF_BASE_DIR)/project/pyrightconfig-base.json $(addprefix --field include=,$(wildcard src/python tools/python)) $(PROJECT) > $@.tmp
 	mv $@.tmp $@
+
+include $(JWBDIR)/make/py-check.mk