diff --git a/nbrmd/nbrmd.py b/nbrmd/nbrmd.py
index 22b3f121c..d2d2267a1 100644
--- a/nbrmd/nbrmd.py
+++ b/nbrmd/nbrmd.py
@@ -102,6 +102,10 @@ def to_notebook(self, text, **kwargs):
 
         if self.ext == '.Rmd':
             find_main_language(metadata, cells)
+        elif self.ext == '.R':
+            if not (metadata.get('main_language') or
+                    metadata.get('language_info', {})):
+                metadata['main_language'] = 'R'
 
         nb = new_notebook(cells=cells, metadata=metadata)
         return nb
@@ -140,6 +144,8 @@ def writes(self, nb, **kwargs):
             default_language = (nb.metadata.get('main_language') or
                                 nb.metadata.get('language_info', {})
                                 .get('name', 'R'))
+            if nb.metadata.get('main_language') == 'R':
+                del nb.metadata['main_language']
         else:
             default_language = get_default_language(nb)
 
diff --git a/tests/knitr-spin.R b/tests/knitr-spin.R
new file mode 100644
index 000000000..7aae90e35
--- /dev/null
+++ b/tests/knitr-spin.R
@@ -0,0 +1,44 @@
+#' This is a special R script which can be used to generate a report. You can
+#' write normal text in roxygen comments.
+#'
+#' First we set up some options (you do not have to do this):
+
+#+ setup, include=FALSE
+library(knitr)
+opts_chunk$set(fig.path = 'figure/silk-')
+
+#' The report begins here.
+
+#+ test-a, cache=FALSE
+# boring examples as usual
+set.seed(123)
+x = rnorm(5)
+mean(x)
+
+#' You can not use here the special syntax {{code}} to embed inline expressions, e.g.
+#' {{mean(x) + 2}}
+#' is the mean of x plus 2.
+#' The code itself may contain braces, but these are not checked.  Thus,
+#' perfectly valid (though very strange) R code such as `{{2 + 3}} - {{4 - 5}}`
+#' can lead to errors because `2 + 3}} - {{4 - 5` will be treated as inline code.
+#'
+#' Now we continue writing the report. We can draw plots as well.
+
+#+ test-b, fig.height=5, fig.width=5
+par(mar = c(4, 4, .1, .1)); plot(x)
+
+#' Actually you do not have to write chunk options, in which case knitr will use
+#' default options. For example, the code below has no options attached:
+
+var(x)
+quantile(x)
+
+#' And you can also write two chunks successively like this:
+
+#+ test-chisq5
+sum(x^2) # chi-square distribution with df 5
+#+ test-chisq4
+sum((x - mean(x))^2) # df is 4 now
+
+#' Done. Call spin('knitr-spin.R') to make silk from sow's ear now and knit a
+#' lovely purse.
diff --git a/tests/knitr-spin.Rmd b/tests/knitr-spin.Rmd
new file mode 100644
index 000000000..dd2b9d37b
--- /dev/null
+++ b/tests/knitr-spin.Rmd
@@ -0,0 +1,51 @@
+This is a special R script which can be used to generate a report. You can
+write normal text in roxygen comments.
+
+First we set up some options (you do not have to do this):
+
+```{r setup, include=FALSE}
+library(knitr)
+opts_chunk$set(fig.path = 'figure/silk-')
+```
+
+The report begins here.
+
+```{r test-a, cache=FALSE}
+# boring examples as usual
+set.seed(123)
+x = rnorm(5)
+mean(x)
+```
+
+You can not use here the special syntax {{code}} to embed inline expressions, e.g.
+{{mean(x) + 2}}
+is the mean of x plus 2.
+The code itself may contain braces, but these are not checked.  Thus,
+perfectly valid (though very strange) R code such as `{{2 + 3}} - {{4 - 5}}`
+can lead to errors because `2 + 3}} - {{4 - 5` will be treated as inline code.
+
+Now we continue writing the report. We can draw plots as well.
+
+```{r test-b, fig.height=5, fig.width=5}
+par(mar = c(4, 4, .1, .1)); plot(x)
+```
+
+Actually you do not have to write chunk options, in which case knitr will use
+default options. For example, the code below has no options attached:
+
+```{r}
+var(x)
+quantile(x)
+```
+
+And you can also write two chunks successively like this:
+
+```{r test-chisq5}
+sum(x^2) # chi-square distribution with df 5
+```
+```{r test-chisq4}
+sum((x - mean(x))^2) # df is 4 now
+```
+
+Done. Call spin('knitr-spin.R') to make silk from sow's ear now and knit a
+lovely purse.
diff --git a/tests/mirror/knitr-spin.ipynb b/tests/mirror/knitr-spin.ipynb
new file mode 100644
index 000000000..482af5a24
--- /dev/null
+++ b/tests/mirror/knitr-spin.ipynb
@@ -0,0 +1,137 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "This is a special R script which can be used to generate a report. You can\n",
+    "write normal text in roxygen comments.\n",
+    "\n",
+    "First we set up some options (you do not have to do this):"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "hide_output": true,
+    "name": "setup"
+   },
+   "outputs": [],
+   "source": [
+    "library(knitr)\n",
+    "opts_chunk$set(fig.path = 'figure/silk-')"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "The report begins here."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "cache": false,
+    "name": "test-a"
+   },
+   "outputs": [],
+   "source": [
+    "# boring examples as usual\n",
+    "set.seed(123)\n",
+    "x = rnorm(5)\n",
+    "mean(x)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "You can not use here the special syntax {{code}} to embed inline expressions, e.g.\n",
+    "{{mean(x) + 2}}\n",
+    "is the mean of x plus 2.\n",
+    "The code itself may contain braces, but these are not checked.  Thus,\n",
+    "perfectly valid (though very strange) R code such as `{{2 + 3}} - {{4 - 5}}`\n",
+    "can lead to errors because `2 + 3}} - {{4 - 5` will be treated as inline code.\n",
+    "\n",
+    "Now we continue writing the report. We can draw plots as well."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "fig.height": 5,
+    "fig.width": 5,
+    "name": "test-b"
+   },
+   "outputs": [],
+   "source": [
+    "par(mar = c(4, 4, .1, .1)); plot(x)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Actually you do not have to write chunk options, in which case knitr will use\n",
+    "default options. For example, the code below has no options attached:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "var(x)\n",
+    "quantile(x)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "And you can also write two chunks successively like this:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "name": "test-chisq5",
+    "noskipline": true
+   },
+   "outputs": [],
+   "source": [
+    "sum(x^2) # chi-square distribution with df 5"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "name": "test-chisq4"
+   },
+   "outputs": [],
+   "source": [
+    "sum((x - mean(x))^2) # df is 4 now"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Done. Call spin('knitr-spin.R') to make silk from sow's ear now and knit a\n",
+    "lovely purse."
+   ]
+  }
+ ],
+ "metadata": {
+  "main_language": "R"
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}
diff --git a/tests/test_knitr_spin.py b/tests/test_knitr_spin.py
new file mode 100644
index 000000000..f8d53bbb4
--- /dev/null
+++ b/tests/test_knitr_spin.py
@@ -0,0 +1,23 @@
+import sys
+import pytest
+import nbrmd
+from .utils import list_all_notebooks
+
+nbrmd.file_format_version.FILE_FORMAT_VERSION = {}
+
+
+@pytest.mark.skipif(sys.version_info < (3, 6),
+                    reason="unordered dict result in changes in chunk options")
+@pytest.mark.parametrize('r_file',
+                         list_all_notebooks('.R'))
+def test_nbrmd_same_as_knitr_spin(r_file, tmpdir):
+    nb = nbrmd.readf(r_file)
+    rmd_nbrmd = nbrmd.writes(nb, ext='.Rmd')
+
+    # Rmd file generated with spin(hair='R/spin.R', knit=FALSE)
+    rmd_file = r_file.replace('.R', '.Rmd')
+
+    with open(rmd_file) as fp:
+        rmd_spin = fp.read()
+
+    assert rmd_nbrmd == rmd_spin