diff --git a/.github/workflows/build-runstats.yml b/.github/workflows/build-runstats.yml
new file mode 100644
index 000000000..6096a0df7
--- /dev/null
+++ b/.github/workflows/build-runstats.yml
@@ -0,0 +1,101 @@
+# SPDX-FileCopyrightText: 2026 The RISE Project
+# SPDX-License-Identifier: MIT
+---
+# Based on the `builds` job of
+# https://github.com/grantjenks/python-runstats/blob/v2.0.0/.github/workflows/release.yml
+name: Build runstats wheels (riscv64)
+
+on:
+  workflow_dispatch:
+    inputs:
+      version:
+        description: 'runstats version to build (git tag without leading v, e.g. 2.0.0)'
+        required: true
+        default: '2.0.0'
+  pull_request:
+    paths:
+      - '.github/workflows/build-runstats.yml'
+      - 'patches/runstats/**'
+
+concurrency:
+  group: ${{ github.workflow }}-${{ inputs.version || '2.0.0' }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read  # to fetch code (actions/checkout)
+
+env:
+  RUNSTATS_VERSION: ${{ inputs.version || '2.0.0' }}
+  MANYLINUX_RISCV64_IMAGE: quay.io/pypa/manylinux_2_39_riscv64
+
+jobs:
+  setup:
+    uses: $/.github/workflows/_setup.yml
+
+  build_wheels:
+    needs: [setup]
+    name: Build runstats ${{ inputs.version || '2.0.0' }} ${{ matrix.python }}-manylinux_riscv64
+    runs-on: ubuntu-24.04-riscv
+    strategy:
+      fail-fast: false
+      matrix:
+        python: ["cp312", "cp313", "cp314", "cp314t"]
+
+    steps:
+      - name: Checkout runstats v${{ env.RUNSTATS_VERSION }}
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
+        with:
+          repository: grantjenks/python-runstats
+          ref: v${{ env.RUNSTATS_VERSION }}
+          persist-credentials: false
+
+      - name: Checkout python-wheels
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
+        with:
+          path: python-wheels
+          persist-credentials: false
+
+      - name: Patch runstats source
+        run: git apply python-wheels/patches/runstats/${{ env.RUNSTATS_VERSION }}/*.patch
+
+      - name: Build wheels
+        uses: pypa/cibuildwheel@1828c10ab37f080699c7b81cea34097c684a7074  # v4.2.0
+        with:
+          output-dir: wheelhouse/
+          only: ${{ matrix.python }}-manylinux_riscv64
+        env:
+          CIBW_MANYLINUX_RISCV64_IMAGE: ${{ env.MANYLINUX_RISCV64_IMAGE }}
+          # setup.py has no [build-system] table, so pypa/build's default isolated
+          # venv never sees CIBW_BEFORE_BUILD's cython install and silently falls
+          # back to a pure-Python wheel (CLAUDE.md gotcha 57).
+          CIBW_BEFORE_BUILD: pip install cython setuptools
+          CIBW_BUILD_FRONTEND: "pip; args: --no-build-isolation"
+          CIBW_TEST_REQUIRES: pytest
+          # test/__init__.py exists, so build-from-checkout's own runstats/ would
+          # shadow the installed wheel under pytest's default import mode; stage
+          # only tests/ into an empty cwd instead (gotcha 25). Also sidesteps
+          # tox.ini's --cov-fail-under=100, which measures unrelated dev checks.
+          CIBW_TEST_SOURCES: tests
+          # setup.py falls back to a pure-Python wheel if cythonize/build_ext raises
+          # (bare try/except around the Extension build) -- assert the compiled
+          # extension actually loaded before trusting the test suite (gotcha 91).
+          CIBW_TEST_COMMAND: >-
+            python -c "import runstats._core; assert runstats._core.__file__.endswith('.so'), runstats._core.__file__"
+            && python -m pytest tests
+            && python tests/benchmark.py
+
+      - uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a  # v7.0.1
+        with:
+          name: runstats-${{ env.RUNSTATS_VERSION }}-${{ matrix.python }}-manylinux_riscv64
+          path: wheelhouse/*.whl
+          if-no-files-found: error
+
+  publish:
+    name: Publish runstats ${{ inputs.version || '2.0.0' }}
+    needs: [setup, build_wheels]
+    permissions:
+      contents: write
+      pull-requests: write
+    uses: $/.github/workflows/_publish-wheel.yml
+    with:
+      artifact-pattern: runstats-${{ inputs.version || '2.0.0' }}-*-manylinux_riscv64
diff --git a/patches/runstats/2.0.0/0001-core-define-Statistics.__rmul__-explicitly-instead-o.patch b/patches/runstats/2.0.0/0001-core-define-Statistics.__rmul__-explicitly-instead-o.patch
new file mode 100644
index 000000000..5d6c2635e
--- /dev/null
+++ b/patches/runstats/2.0.0/0001-core-define-Statistics.__rmul__-explicitly-instead-o.patch
@@ -0,0 +1,38 @@
+From 05bc58febe93abc362e2204aaa7d4504d2bc24a8 Mon Sep 17 00:00:00 2001
+From: Ludovic Henry <git@ludovic.dev>
+Date: Mon, 7 Sep 2026 14:56:43 +0200
+Subject: [PATCH] core: define Statistics.__rmul__ explicitly instead of
+ aliasing __mul__
+
+Cython 3.x compiles cdef class special methods from the textual "def" it
+sees; the "__rmul__ = __mul__" alias only adds a dict entry after the
+class body runs, it does not retroactively wire the type's nb_multiply
+slot to also try the reflected method, so "2 * stats" raises TypeError
+on the compiled _core.Statistics while the pure-Python core.Statistics
+(an ordinary class, where CPython's own slot machinery checks __dict__
+dynamically) still supports it. Affects any build against a modern
+Cython, independent of architecture.
+
+Upstream-Status: To upstream [not yet submitted; RISE's python-wheels port policy disallows opening issues/PRs against third-party repos]
+---
+ runstats/core.py | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+diff --git a/runstats/core.py b/runstats/core.py
+index bc9f14e..3af5275 100644
+--- a/runstats/core.py
++++ b/runstats/core.py
+@@ -241,7 +241,9 @@ class Statistics:
+         # https://stackoverflow.com/q/33218006/232571
+         return that._mul(self)  # pragma: no cover
+ 
+-    __rmul__ = __mul__
++    def __rmul__(self, that):
++        """Multiply by a scalar to change Statistics weighting."""
++        return self.__mul__(that)
+ 
+     def _imul(self, that):
+         """Multiply by a scalar to change Statistics weighting in-place."""
+-- 
+2.50.1 (Apple Git-155)
+