diff --git a/R/add_header_left.R b/R/add_header_left.R
new file mode 100644
index 0000000..b91a38c
--- /dev/null
+++ b/R/add_header_left.R
@@ -0,0 +1,76 @@
+#' Add a header column
+#'
+#' @description Experimenting. Please don't use it in production
+#'
+#' @export
+add_header_left <- function(kable_input, header = NULL, header_name = "") {
+  if (is.null(header)) return(kable_input)
+  kable_format <- attr(kable_input, "format")
+  if (!kable_format %in% c("html", "latex")) {
+    stop("Please specify output format in your kable function. Currently ",
+         "generic markdown table using pandoc is not supported.")
+  }
+  if (kable_format == "html") {
+    return(add_header_left_html(kable_input, header, header_name))
+  }
+  if (kable_format == "latex") {
+    return(add_header_left_latex(kable_input, header, header_name))
+  }
+}
+
+# HTML
+add_header_left_html <- function(kable_input, header, header_name) {
+  kable_attrs <- attributes(kable_input)
+  kable_xml <- read_xml(as.character(kable_input), options = "COMPACT")
+  kable_thead <- xml_tpart(kable_xml, "thead")
+  kable_tbody <- xml_tpart(kable_xml, "tbody")
+
+  new_header <- paste0(
+    '<th style="text-align:center;" rowspan="',
+    length(xml_children(kable_thead)), '">', header_name, '</th>'
+  )
+  new_header <- read_xml(new_header, options = c("COMPACT"))
+  xml_add_child(xml_child(kable_thead, 1), new_header, .where = 0)
+
+  header <- standardize_rowheader_input(header, length(xml_children(kable_tbody)))
+  for (i in 1:nrow(header)) {
+    new_row_item <- paste0(
+      '<td style="text-align:center; vertical-align: middle;" rowspan="',
+      header$rowspan[i], '">', header$header[i], '</td>')
+    new_row_item <- read_xml(new_row_item, options = "COMPACT")
+    target_row <- xml_child(kable_tbody, header$row[i])
+    xml_add_child(target_row, new_row_item, .where = 0)
+  }
+
+  out <- structure(as.character(kable_xml), format = "html",
+                   class = "knitr_kable")
+  attributes(out) <- kable_attrs
+  return(out)
+}
+
+standardize_rowheader_input <- function(header, n_row) {
+  header_names <- names(header)
+
+  if (is.null(header_names)) {
+    return(data.frame(header = header, row = 1:length(header),
+                      rowspan = 1, row.names = NULL))
+  }
+
+  names(header)[header_names == ""] <- header[header_names == ""]
+  header[header_names == ""] <- 1
+  header_names <- names(header)
+  header <- as.numeric(header)
+  names(header) <- header_names
+  if (sum(header) < n_row) {
+    header <- c(header, " " = n_row - sum(header))
+  }
+  row_pos <- c(1, cumsum(header)[-length(header)] + 1)
+  return(data.frame(
+    header = names(header),
+    row = row_pos, rowspan = header, row.names = NULL
+    ))
+}
+
+add_header_left_latex <- function(kable_input, header, header_name) {
+  return(kable_input)
+}
diff --git a/R/util.R b/R/util.R
index 3f5c470..a500879 100644
--- a/R/util.R
+++ b/R/util.R
@@ -67,3 +67,5 @@
   mapping_matrix <- data.frame(mapping_matrix)
   return(mapping_matrix)
 }
+
+