Unknown
19<sup>th</sup> century <div style="display: none;">date QS:P571,+1850-00-00T00:00:00Z/7</div>
The Japanese book "御三卿一橋徳川家 (Gosankyō Hitotsubashi Tokugawake)", Ibaraki Prefectural Museum of History(<a href="https://ja.wikipedia.org/wiki/%E8%8C%A8%E5%9F%8E%E7%9C%8C%E7%AB%8B%E6%AD%B4%E5%8F%B2%E9%A4%A8" class="extiw" title="ja:茨城県立歴史館">茨城県立歴史館</a>), 2003