In Jekyll, is there a concise way to render a Markdown partial?

I was looking for this too, it was a PITA discovering how to do it, not much Google content, the most exact finding was a gist that wouldn’t work here… dead simple solution:

./_plugins/markdown_tag.rb:

module Jekyll
  class MarkdownTag < Liquid::Tag
    def initialize(tag_name, text, tokens)
      super
      @text = text.strip
    end
    require "kramdown"
    def render(context)
      tmpl = File.read File.join Dir.pwd, "_includes", @text
      Jekyll::Converters::Markdown::KramdownParser.new(Jekyll.configuration()).convert(tmpl)
    end
  end
end
Liquid::Template.register_tag('markdown', Jekyll::MarkdownTag)

UPDATE: blog with usage example: https://web.archive.org/web/20161207125751/http://wolfslittlestore.be/2013/10/rendering-markdown-in-jekyll/