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

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