These are the sources I consulted while writing this series of articles. The majority of sources are secondary sources (since I am unlikely to be able to access, or even read classical Japanese primary sources) and in Japanese (which I can read, and have judged to be sufficiently reliable).
handoroya. (2014, June 5). 「ちょっと風呂入ってくる」の一局. はんどろやノート. https://blog.goo.ne.jp/handoroya/e/9da92cb3d1dd0751ad1be360b635d296
Oohashi, K. (n.d.-a). 将棋大綱. 詰将棋博物館. Retrieved March 28, 2021, from http://park6.wakwak.com/~k-oohasi/shougi/html/taikou/taikou00.html
Oohashi, K. (n.d.-b). 将棋駒競. 詰将棋博物館. Retrieved March 28, 2021, from http://park6.wakwak.com/~k-oohasi/shougi/html/komakura/komakura00.html
Oohashi, K. (n.d.-c). 象戯手鑑. 詰将棋博物館. Retrieved March 28, 2021, from http://park6.wakwak.com/~k-oohasi/shougi/html/tekagami/tekagami00.html
Oohashi, K. (n.d.-d). 象戯造物. 詰将棋博物館. Retrieved March 28, 2021, from http://park6.wakwak.com/~k-oohasi/shougi/html/keityou/keityou00.html
Oohashi, K., & 門脇芳雄. (n.d.-a). 将棋無双. 詰将棋博物館. Retrieved March 28, 2021, from http://park6.wakwak.com/~k-oohasi/shougi/html/musou/musou00.html
Oohashi, K., & 門脇芳雄. (n.d.-b). 御撰象棊攷格. 詰将棋博物館. Retrieved March 28, 2021, from http://park6.wakwak.com/~k-oohasi/shougi/html/koukaku/koukaku00.html
Oohashi, K., & 門脇芳雄. (n.d.-c). 象棋百番奇巧図式. 詰将棋博物館. Retrieved March 28, 2021, from http://park6.wakwak.com/~k-oohasi/shougi/zukou/zukou00.html
Rath, E. C. (2016). Interlude Iemoto: The family head system. In J. Salz (Ed.), A History of Japanese Theatre (1st ed., pp. 99–101). Cambridge University Press. https://doi.org/10.1017/CBO9781139525336.010
ブライト＆まるた. (2020, February 24). 【御城将棋】江戸時代史上最高傑作と言われる棋譜を元奨励会三段が解説. https://www.nicovideo.jp/watch/sm36414536
中世の日本将棋／大将棋・中将棋・小将棋…. (n.d.). syougi-a.net. Retrieved March 28, 2021, from https://syougi-a.net/sekai/sort.html
伊藤宗印 (2代). (n.d.). Wikipedia (JP). Retrieved March 28, 2021, from https://ja.wikipedia.org/wiki/%E4%BC%8A%E8%97%A4%E5%AE%97%E5%8D%B0_(2%E4%BB%A3)
伊藤宗看（初代）. (1649). 象戯図式. http://www.library-noda.jp/homepage/digilib/shogi/45.html
伊藤家の紹介. (2014, June 26). 関西将棋会館. https://web.archive.org/web/20140626035727/http://www.shogi.or.jp/kansai/museum/ito.html
史上最強棋士はだれか 将棋AIが出した答えは. (2017, October 25). DG Lab Haus. https://media.dglab.com/2017/10/25-shogiai-01/
大平将彦. (2006). 江戸時代の将棋―将棋家と将棋の普及 [Seminar paper]. http://www.ic.daito.ac.jp/~uriu/thesis/2006/ohira.html
大橋分家の紹介. (2014, June 26). 関西将棋会館. https://web.archive.org/web/20140626035752/http://www.shogi.or.jp/kansai/museum/ohashibun.html
大橋宗桂. (n.d.). コトバンク. Retrieved March 28, 2021, from https://kotobank.jp/word/%E5%A4%A7%E6%A9%8B%E5%AE%97%E6%A1%82-39499
大橋宗桂 (初代). (n.d.). Wikipedia (JP). Retrieved March 28, 2021, from https://ja.wikipedia.org/wiki/%E5%A4%A7%E6%A9%8B%E5%AE%97%E6%A1%82_(%E5%88%9D%E4%BB%A3)
大橋宗桂（五代）. (1820). 象戯手鑑. http://www.library-noda.jp/homepage/digilib/shogi/46.html
大橋宗桂（初代）. (1703). 象戯力草／宗桂指南抄. http://www.library-noda.jp/homepage/digilib/shogi/39.html
大橋家. (n.d.). Wikipedia (JP). Retrieved March 28, 2021, from https://ja.wikipedia.org/wiki/%E5%A4%A7%E6%A9%8B%E5%AE%B6
大橋家の紹介. (2014, June 25). 関西将棋会館. https://web.archive.org/web/20140625030816/http://www.shogi.or.jp/kansai/museum/ohashi.html
家元. (n.d.). Wikipedia (JP). Retrieved March 28, 2021, from https://ja.wikipedia.org/wiki/%E5%AE%B6%E5%85%83
家元三家・歴代名人～将棋連盟誕生まで. (n.d.). syougi-a.net. Retrieved March 28, 2021, from https://syougi-a.net/sekai/meijin.html
対局者プロフィール（江戸時代後期）. (2016, May 9). 関西将棋会館. https://web.archive.org/web/20160509191004/http://www.shogi.or.jp/kansai/museum/profile2.html
将棋. (n.d.). Wikipedia (JP). Retrieved March 28, 2021, from https://ja.wikipedia.org/wiki/%E5%B0%86%E6%A3%8B
将棋プロ・家康と家元・段位制度の誕生. (n.d.). syougi-a.net. Retrieved March 28, 2021, from https://syougi-a.net/sekai/tokugawa.html
将棋所—御城将棋. (n.d.). Wikipedia (JP). Retrieved March 28, 2021, from https://ja.wikipedia.org/wiki/%E5%B0%86%E6%A3%8B%E6%89%80#%E5%BE%A1%E5%9F%8E%E5%B0%86%E6%A3%8B
御城将棋. (2015, July 6). 温故知新. http://onkotisin.org/osiro/osiro.htm
御撰象棊攷格. (n.d.). National Archives of Japan. Retrieved March 29, 2021, from http://www.archives.go.jp/exhibition/digital/shogunnoarchives/contents/42.html
徳川家治. (n.d.-a). コトバンク. Retrieved March 28, 2021, from https://kotobank.jp/word/%E5%BE%B3%E5%B7%9D%E5%AE%B6%E6%B2%BB-19079
徳川家治. (n.d.-b). Wikipedia (JP). Retrieved March 28, 2021, from https://ja.wikipedia.org/wiki/%E5%BE%B3%E5%B7%9D%E5%AE%B6%E6%B2%BB
松本博文. (2018, January 25). 広辞苑にも誤りあり？ 「伊藤宗看」「将棋所」の記述をめぐって. Yahoo! News Japan. https://news.yahoo.co.jp/byline/matsumotohirofumi/20180125-00080843/
檜垣是安. (n.d.). Wikipedia (JP). Retrieved March 28, 2021, from https://ja.wikipedia.org/wiki/%E6%AA%9C%E5%9E%A3%E6%98%AF%E5%AE%89
江戸時代の将棋－萩藩の強豪“真甫”－. (2014). http://archives.pref.yamaguchi.lg.jp/user_data/upload/File/smallexhibition/H26-08.pdf
福田稔. (2014a, February 4). 『献上図式』の献上年月日. 詰将棋一番星. http://1banboshi.on.coocan.jp/page09-01(37).htm
福田稔. (2014b, May 3). 『献上図式』の献上年月日（後）. 詰将棋一番星. http://1banboshi.on.coocan.jp/page09-01(40).htm
西山松之助. (1982). 西山松之助著作集. 吉川弘文館.
金本奈絵. (2016, July 27). 思わず「へぇ〜」と頷く将棋の歴史トリビア5つ. I-tsu-tsu blog. https://www.i-tsu-tsu.co.jp/blog/trivia-of-history-of-shogi/