An old manuscript called “Komatsu-jyou narabini Mimyoukou Yourou Igo Jijyou 小松城并微妙公養老以後事状” , which was written by Tomita Kagechika(1799, 富田景周) serving the highest official (Jyouban 城番) in charge of Komatsu Castle for the period of 1780-1785, describes the watercourses in Komatsu Castle as follows, where the subsection numbers are inserted by the shrine office::
1) The source of canal water of Komatsu Castle is water from Kakehashi-gawa(梯川）, where its frontal water-flow（suikou, 水口）is in front of Bairin-in(梅林院）. Canal water flows, beneath Geta-bashi(下駄橋）, down to Mattoh-machi(松任町）and then ,via the back of Chikuwa-bata(千桑畑）, reaches Nakayabu(中藪）.
2) Water then splits into two flows. One of two flows travels around the back of worriors’ houses of Umamawari（馬廻）, go, beneath Kita-no-shou-bashi (北庄橋）, to Hirodokoro（広処）where two flows merge and goes to the river mouth.
3) Also one flow goes beneath Funadomari-Nimai-bashi（舟止二枚橋）and enters Hakuchou-zan（白鳥塹）. From here, water goes between Makishima (牧島）and Nakadoi（中土居）, passes through the joins of Biwajima （琵琶島）, flows in front of Atago（愛宕）
4) and, via beneath Nagabashi (長橋), enters the innermost canal where water splits into two flows. Left-side water flows beneath Sujichigai-bashi（筋違橋）and then between Yoshijima (葭島）and Gakuya-tuzuki（楽屋つづき）in making a tour around Honmaru (本丸, the main Compound). Right-side water flows alongside Biwajima（琵琶島）, then goes beneath Daidokoro-bashi（台所橋）and Kuruma-bashi（車橋）, and travels around Honmaru.
5) Two water-flows then merge to become one flow which, in front of Rau (楼, the tall building), flows down to Hakuchou-zan（白鳥塹）.”(Kitano (1999b) in KS, p272)
Figure 1 illustrates watercourses described by Tomita Kagechika in terms of the map held by the shrine, where the map is estimated, in terms of the comparison of worriors’ names, especially the name of Nakamura Hikozaemon 中村彦左衛門, written in worriors’ houses with the assumption year of Komatsu-On-Bugu-Bugyou（小松御武具奉行）and the resignation year of Komatsu-On-Sakuji-Bugyou（小松御作事奉行）(Kitano (1999a), pp.260-261), to be drawn sometime between 1841 and 1853. Three types of lines are used in Figure 1: Most watercourses are drawn in thin white lines, two watercourses making a tour around Honmaru in two bold white lines, and two dotted lines indicate the frontal water-flow in front of the shrine and the rear water-flow in front of Rau on Tenshudai.
Copyright Komatsu Tenmangu 2008
Figure 1 Watercourses in Komatsu Castle
Commentary written on a map, held by Kanazawa Municipal Government Library and called “Komatsu-jyou Gohonmaru Goten no Ezu”(小松城御本丸御殿之図), indicates that the site of the main compound (Honmaru) as well as Tenshudai was formerly swamp land and the castle lord, Maeda Toshitune , ordered to build the Honmaru on land reclaimed from swamp (Inumaru and Miura (1999, p391). This reference apparently indicates Toshitune’s intension to remodel Komatsu Castle which was previously built by Murakami Yorikatu（村上頼勝） and Niwa Nagashige(丹羽長重).