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. Gobara Castle
  27. Gokan Castle
  28. Hachigata Castle
  29. Hachioji Castle
  30. Hagi Castle
  31. Haibara Castle
  32. Hakusan Castle
  33. Hakusan Castle (Harima)
  34. Hamada Castle
  35. Hanawa Castle
  36. Hasedo Castle
  37. Hayashikojo Castle
  38. Hayashiohjo Castle
  39. Hekirichi Jinya
  40. Hirai Castle
  41. Hirai Kanayama Castle
  42. Hyakusaiji Castle
  43. Ichinomiya Castle
  44. Imai Castle
  45. Inukai Castle
  46. Ishigakiyama Ichiya Castle
  47. Iwabitsu Castle
  48. Iwamura Castle
  49. Izu Nagahama Castle
  50. Jindaiji Castle
  51. Jofukuji Castle
  52. Kanaiyama Castle
  53. Kanayama Castle
  54. Kanazawa Castle
  55. Kannonji Castle
  56. Karakai Castle
  57. Karasawayama Castle
  58. Karasuyama Castle
  59. Kasama Castle
  60. Kaseyama Castle
  61. Kashiwara Castle
  62. Kasugayama Castle
  63. Kasumi Castle
  64. Katsunuma Castle
  65. Katsunumashi Yakata
  66. Kawahara Castle
  67. Kawamura Castle
  68. Kazurayama Castle
  69. Kirihara Castle
  70. Kogane Castle
  71. Kokokuji Castle
  72. Komaki Castle
  73. Komoro Castle
  74. Konomine Castle
  75. Konosumiyama Castle
  76. Koshigoe Castle
  77. Kozukue Castle
  78. Kuma Castle
  79. Kumamoto Castle
  80. Kunohe Castle
  81. Kururi Castle
  82. Kuwabara Castle
  83. Mariko Castle
  84. Masugatayama Castle
  85. Masuo Castle
  86. Matsukura Castle
  87. Matsuo Castle
  88. Matsuyama Castle (Gunma)
  89. Matsuyama Castle (Saitama)
  90. Minagawa Castle
  91. Minokubi Castle
  92. Minowa Castle
  93. Mito Castle
  94. Morioka Castle
  95. Moriya Castle
  96. Moriyama Castle
  97. Moroto Castle
  98. Motosakura Castle
  99. Mumo Castle
  100. Nabekura Castle
  101. Naegi Castle
  102. Nagashino Castle
  103. Nagoya Castle
  104. Nagurumi Castle
  105. Naka Castle
  106. Narisawa Castle
  107. Nasu Kanda Castle
  1. Niitakayama Castle
  2. Nirayama Castle
  3. Nochiseyama Castle
  4. Numata Castle
  5. Oba Castle
  6. Obata Castle
  7. Obata Jin'ya
  8. Obiki Castle
  9. Oda Castle
  10. Odaka Castle
  11. Odani Castle
  12. Odano Castle
  13. Odawara Castle
  14. Oeda Castle
  15. Ogawa Castle
  16. Ogimachi Castle
  17. Ogoe Castle
  18. Ogura Castle
  19. Ohkusa Castle
  20. Okami Castle
  21. Okkoshi Castle
  22. Oko Castle
  23. Omori Castle
  24. Oogo Castle
  25. Oohara Castle
  26. Oomizo Castle
  27. Ori Castle
  28. Osaka Castle (Ibaraki)
  29. Owari Ohno Castle
  30. Oyama Castle
  31. Rikan Castle
  32. Saimyoji Castle
  33. Sakasai Castle
  34. Sakata Castle
  35. Sakura Castle
  36. Sanada Palace
  37. Sanadahonjo Castle
  38. Sano Castle
  39. Sasao Castle
  40. Sasayama Castle
  41. Sashiki Castle
  42. Seiryuin
  43. Senpuku Castle
  44. Setagaya Castle
  45. Shakujii Castle
  46. Shigiyama Castle
  47. Shimizu Castle
  48. Shinpu Castle
  49. Shishiku Castle
  50. Shiwa Castle
  51. Soma Nakamura Castle
  52. Sugaya Yakata
  53. Sugiyama Castle
  54. Suwahara Castle
  55. Takai Castle
  56. Takane Castle
  57. Takatenjin Castle
  58. Takato Castle
  59. Takatome Castle
  60. Takatori Castle
  61. Takeda Castle
  62. Taki Castle
  63. Takiyama Castle
  64. Tamaru Castle
  65. Tanagura Castle
  66. Tateyama Castle (Yamagata)
  67. Tatsuno Castle
  68. Tenjinyama Castle
  69. Tenpaku Castle
  70. Tobiyama Castle
  71. Toishi Castle
  72. Tokiwa Castle
  73. Tokura Castle
  74. Torigoe Castle
  75. Torinji Castle
  76. Tsukui Castle
  77. Tsumagi Castle
  78. Tsumago Castle
  79. Tsutsujigasaki Palace
  80. Tsuwano Castle
  81. Uda Matsuyama Castle
  82. Ueda Castle
  83. Uehara Castle
  84. Ushiku Castle
  85. Usui Castle
  86. Usuida Shukuuchi Fort
  87. Washio Castle
  88. Yagi Castle
  89. Yamabe Castle
  90. Yamagami Castle
  91. Yamagata Castle
  92. Yamagata Castle (Hitachi)
  93. Yamanaka Castle
  94. Yamazaki Castle
  95. Yanagawa Castle
  96. Yato Castle
  97. Yogaisan Castle
  98. Yoshida Castle
  99. Yoshida Castle (Ibaraki)
  100. Yoshinogari
  101. Yumurayama Castle
  102. Yunagaya Jin'ya
  103. Yuzawa Castle
  104. Yuzuki Castle
  105. Zen Castle
  106. Zeze Castle

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