Trenches / 空堀

This is a subtype of Features

Trenches, ditches, empty moats, or dry moats are one type of earthworks that cover a wide range of trench like fortifications around castles. In flatland castles they are often similar in structure to water moats but without the water. Both water moats or dry trenches have their own unique advantages and disadvantages. For example, it can be harder for intruders to hide in a dry moat and there no natural water sounds that might disguise entry. The slick clay sides of many castles in the Kanto region were especially slippery and difficult to climb. I have had a difficult time even in hiking boots getting up only slight slope where there is no grass for traction. On the other hand, water moats, where feasible, can be a good psychological deterrent. Attackers don't know how deep they are or what is underneath. A wet intruder will likely leave a trail and they will need to expend more energy to get across.

When you see photos or visit these locations yourself you may think that these trenches are shallow and would not be much of a deterrent but keep in mind that they have filled with leaves and dirt and have been eroded significantly over the last 400 years. What is now a meter or less deep may have been two or three times that deep at one time.

Some terms related to trenches that you may see include:

Horikiri (堀切)

This is a deep trench cut across a mountain ridge to impede attackers from easily climbing the ridge. You see a lot of these on the path to mountaintop castles and it's usually the first sign that you've entered a castle. Unless there are signs to point them out or you are familiar with seeing horikiri you might not notice them at all. But, if you think about it, such a sudden steep dip in a ridge is very unnatural.

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Yokobori (横堀)

A horizontal trench across a slope or mountain. It can also provide an easier route for defenders to cross a slope.

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Tatebori (竪堀)

A vertical trench running down a slope. It can be used to impede attackers from easily crossing a slope and can force them into a kill zone.

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Unejotatebori (畝状竪堀)

Several parallel tatebori across one slope on a mountaintop castle. They may be difficult to see if the are on a steep side of the castle that you cannot get to.

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Shojibori (障子堀)

A wider trench with square depressions carved out. It forces attackers to either walk the narrow ridges and be easily fired upon or scale up and down the slick clay walls putting them in vulnerable positions and using a lot of physical energy. These are often attributed to the Hojo but the Hideyoshi's Osaka Castle had great shojibori too. Unfortunately you can not longer see them. The only really good shojibori you can see today are at Yamanaka Castle in Shizuoka but many more have been excavated and reburied over the years.

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Unebori (畝堀)

A trench with ridges across them. This is similar in design to the shojibori but instead of a "waffle" like design it is only a single row of dugout depressions.

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Empty Moats (空堀)

These are the moats you are more likely to see at flatland castles. They are similar in size and shape to water moats but without the water.

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Castles with Trenches

  1. Akizuki Castle
  2. Akutagawasan Castle
  3. Ansho Castle
  4. Aoyagi Castle
  5. Aoyama Castle
  6. Arikoyama Castle
  7. Asaba Castle
  8. Ashigara Castle
  9. Asonuma Castle
  10. Asuke Castle
  11. Azuchi Castle
  12. Bitchu Matsuyama Castle
  13. Bitchu Takamatsu Castle
  14. Chigasaki Castle
  15. Chihaya Castle
  16. Echizen Ohno Castle
  17. Fujihashi Castle (Tokyo)
  18. Fujita Castle
  19. Fukazawa Castle
  20. Funaoka Castle
  21. Futamata Castle
  22. Futoge Castle
  23. Ganjaku Castle
  24. Gassan Toda Castle
  25. Gifu Castle
  26. Gion Castle
  27. Gobara Castle
  28. Gokan Castle
  29. Hachigata Castle
  30. Hachioji Castle
  31. Hagi Castle
  32. Haibara Castle
  33. Hakusan Castle
  34. Hakusan Castle (Harima)
  35. Hamada Castle
  36. Hanamaki Castle
  37. Hanawa Castle
  38. Hanazono Castle
  39. Hanazono Mitake Castle
  40. Hasedo Castle
  41. Hayashikojo Castle
  42. Hayashiohjo Castle
  43. Hekirichi Jinya
  44. Hirai Castle
  45. Hirai Kanayama Castle
  46. Hyakusaiji Castle
  47. Ichinomiya Castle
  48. Imai Castle
  49. Inukai Castle
  50. Ishigakiyama Ichiya Castle
  51. Ishigami Castle
  52. Isobe Castle
  53. Iwabitsu Castle
  54. Iwamura Castle
  55. Izu Nagahama Castle
  56. Jindaiji Castle
  57. Jofukuji Castle
  58. Kanaiyama Castle
  59. Kanao Yogaisan Castle
  60. Kanayama Castle
  61. Kanazawa Castle
  62. Kanegasaki Castle (Iwate)
  63. Kannonji Castle
  64. Karakai Castle
  65. Karasawayama Castle
  66. Karasuyama Castle
  67. Kasama Castle
  68. Kaseyama Castle
  69. Kashiwara Castle
  70. Kasugayama Castle
  71. Kasumi Castle
  72. Katsunuma Castle
  73. Katsunumashi Yakata
  74. Kawahara Castle
  75. Kawamura Castle
  76. Kazurayama Castle
  77. Kirihara Castle
  78. Kogane Castle
  79. Kokokuji Castle
  80. Komaki Castle
  81. Komoro Castle
  82. Konomine Castle
  83. Konosumiyama Castle
  84. Koshigoe Castle
  85. Koyama Castle
  86. Kozukue Castle
  87. Kubota Castle
  88. Kuma Castle
  89. Kumamoto Castle
  90. Kunohe Castle
  91. Kurobane Castle
  92. Kururi Castle
  93. Kuwabara Castle
  94. Mariko Castle
  95. Masugatayama Castle
  96. Masuo Castle
  97. Matsuida Castle
  98. Matsukura Castle
  99. Matsuo Castle
  100. Matsuyama Castle (Gunma)
  101. Matsuyama Castle (Saitama)
  102. Minagawa Castle
  103. Minokubi Castle
  104. Minowa Castle
  105. Mito Castle
  106. Morioka Castle
  107. Moriya Castle
  108. Moriyama Castle
  109. Moroto Castle
  110. Motosakura Castle
  111. Mumo Castle
  112. Musashi Masugatayama Castle
  113. Mutsu Iwasaki Castle
  114. Nabekura Castle
  115. Naegi Castle
  116. Nagashino Castle
  1. Nagoya Castle
  2. Nagurumi Castle
  3. Naka Castle
  4. Narisawa Castle
  5. Nasu Kanda Castle
  6. Niitakayama Castle
  7. Nirayama Castle
  8. Nochiseyama Castle
  9. Numata Castle
  10. Oba Castle
  11. Obata Castle
  12. Obata Jin'ya
  13. Obiki Castle
  14. Oda Castle
  15. Odaka Castle
  16. Odani Castle
  17. Odano Castle
  18. Odawara Castle
  19. Oeda Castle
  20. Ogawa Castle
  21. Ogimachi Castle
  22. Ogoe Castle
  23. Ogura Castle
  24. Ohkusa Castle
  25. Okami Castle
  26. Okkoshi Castle
  27. Oko Castle
  28. Omori Castle
  29. Oogo Castle
  30. Oohara Castle
  31. Oomizo Castle
  32. Ori Castle
  33. Osaka Castle (Ibaraki)
  34. Otawara Castle
  35. Owari Ohno Castle
  36. Rikan Castle
  37. Saimyoji Castle
  38. Sakasai Castle
  39. Sakata Castle
  40. Sakura Castle
  41. Sanada Palace
  42. Sanadahonjo Castle
  43. Sano Castle
  44. Sasao Castle
  45. Sasayama Castle
  46. Sashiki Castle
  47. Seiryuin
  48. Sekinomori Castle
  49. Senpuku Castle
  50. Setagaya Castle
  51. Shakujii Castle
  52. Shigiyama Castle
  53. Shimizu Castle
  54. Shinpu Castle
  55. Shishiku Castle
  56. Shiwa Castle
  57. Soma Nakamura Castle
  58. Sugaya Yakata
  59. Sugiyama Castle
  60. Suwahara Castle
  61. Tage Castle
  62. Takai Castle
  63. Takane Castle
  64. Takatenjin Castle
  65. Takato Castle
  66. Takatome Castle
  67. Takatori Castle
  68. Takatsuki Castle (Tokyo)
  69. Takeda Castle
  70. Taki Castle
  71. Takiyama Castle
  72. Tamaru Castle
  73. Tanagura Castle
  74. Tateyama Castle (Yamagata)
  75. Tatsuno Castle
  76. Tenjinyama Castle
  77. Tenpaku Castle
  78. Tobiyama Castle
  79. Toishi Castle
  80. Tokiwa Castle
  81. Tokura Castle
  82. Tonomi-no-saku
  83. Torigoe Castle
  84. Torinji Castle
  85. Tsukui Castle
  86. Tsumagi Castle
  87. Tsumago Castle
  88. Tsutsujigasaki Palace
  89. Tsuwano Castle
  90. Uda Matsuyama Castle
  91. Ueda Castle
  92. Uehara Castle
  93. Ushiku Castle
  94. Usui Castle
  95. Usuida Shukuuchi Fort
  96. Washi Castle
  97. Washio Castle
  98. Yagi Castle
  99. Yamabe Castle
  100. Yamagami Castle
  101. Yamagata Castle
  102. Yamagata Castle (Hitachi)
  103. Yamanaka Castle
  104. Yamazaki Castle
  105. Yanagawa Castle
  106. Yato Castle
  107. Yogaisan Castle
  108. Yoshida Castle
  109. Yoshida Castle (Ibaraki)
  110. Yoshinogari
  111. Yumurayama Castle
  112. Yunagaya Jin'ya
  113. Yuzawa Castle
  114. Yuzuki Castle
  115. Zen Castle
  116. Zeze Castle

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