watch the trap door! a japanese architect's solution to an age old problem

watch the trap door! a japanese architect's solution to an age old problem

on the outside, there isn’t a whole lot special about this japanese home. like most of its neighbors, it’s a 50-year-old ready built home; yet, after a recent renovation this abode has a few unique features, including a trap door. it’s the project of an architecture firm called persimmon hills.

trap door japan house
all images by kenta hasegawa



the dwelling was designed and built by the architect for his mother. he incorporated her feedback and needs to make the home ideal for her purposes and comfort. the architect also claims to have gotten a hand from her in the construction, thanks mom. the project was fairly simple and the design focused on one problem more than any other — i.e. bringing light into the dark abode that has no courtyards. the easy solution seems fairly obvious now when presented, but it was kind of a breakthrough and something you don’t see everyday.

trap door japan house
the upstairs with the trap door closed 



the architect’s solution was to install a trap door between floors. the bottom is painted white and this allows the light from a nearby window to reflect off it and shine down into the space below. the upstairs can be further utilized by guests with the pull of a rope. this way the mother can unitize her house at its fullest potential.

trap door japan house
the architects mother working downstairs with the aid of natural light

trap door japan house
a depiction of the simple system

trap door japan house
and once again closed

trap door japan house
another shot of the upstairs

trap door japan house
a close up of the system

trap door japan house
the architect’s playful use of materials 

trap door japan house
fine woodwork depicted in the trap door

trap door japan house
the open plan of the home

trap door japan house
truly a comfortable space

trap door japan house
the simple house has more than meets the eye



project info:


architect: yusuke kakinoki + shuhei hirooka / persimmon hills architects
principal use: private residence
construction: tomohisa ito, shuhei hirooka, hiroyuki shimada, jumpei komori, kota sugimoto, katsuya yamagishi, ryohei nishimoto
photography: kenta hasegawa
building area: 32 sqm
total floor area: 56 sqm
number of stories: 2 stories
structure: wood

  • Very cool idea! I like the mix of materials.

    How much does the door weigh? I would have probably used a crank and pulley system, which would be easier to operate and wouldn’t require the large galvanized pipes.

    I also wonder what this room looked like originally. It appears that most of the 4×4 posts are notched out for some reason.

    bj says:
  • A smart solution! In the Alps, this type of door was used in every house. In my new one, I installed one with a counterweight: the door can be opened without effort and remains in any desired position. :-)k

    kuno prey says:
  • Glass is quite rea$onable, and technically stronger than ever before. Cleaner look. Safer solution.

    Higgs Merino says:
  • Running the rope over the pipe works against you when lifting as you must pull harder to overcome the friction. When lowering, the friction makes it a little bit easier to control the door as inertia tries to speed it up.

    The addition of a pulley at the pipe and another one at the door would allow the line to be rigged in “two parts” and cut the required pull in half to handle the door.

    The system would remain simple yet be much easier to operate.

    Bob Peterson says:
  • As mentioned above a glass cover, or some sort of cargo mesh, over the trap door space makes sense. Present design is wicked falling trap for the unaware.

    andy a says:
  • But is the architect’s mom strong enough to lift this door? Because at one point in her life she might need to ask her son to change this solution, it looks quite heavy. Even so, such a great idea! I’d love to live in this little house 🙂

    Elli Aho says:

have something to add? share your thoughts in our comments section below.
all comments are reviewed for the purposes of moderation before publishing.

comments policy
designboom's comment policy guidelines
generally speaking, if we publish something, it's because we're genuinely interested in the subject. we hope you'll share this interest and if you know even more about it, please share! our goal in the discussion threads is to have good conversation and we prefer constructive opinions. we and our readers have fun with entertaining ones. designboom welcomes alerts about typos, incorrect names, and the like.
the correction is at the discretion of the post editor and may not happen immediately.

what if you disagree with what we or another commenter has to say?
let's hear it! but please understand that offensive, inappropriate, or just plain annoying comments may be deleted or shortened.

- please do not make racist, sexist, anti-semitic, homophobic or otherwise offensive comments.
- please don't personally insult the writers or your fellow commenters.
- please avoid using offensive words, replacing a few letters with asterisks is not a valid workaround.
- please don't include your website or e-mail address in your comments for the purpose of self-promotion.
- please respect jury verdicts and do not discuss offensively on the competition results
(there is only one fist prize, and designboom usually asks renown professionals to help us to promote talent.
in addition to the awarded designs, we do feel that almost all deserve our attention, that is why we publish
the best 100-200 entries too.)

a link is allowed in comments as long as they add value in the form of information, images, humor, etc. (links to the front page of your personal blog or website are not okay). unwelcome links (to commercial products or services of others, offensive material etc. ) will be redacted. and, ... yes, spam gets banned. no, we do not post fake comments.


a diverse digital database that acts as a valuable guide in gaining insight and information about a product directly from the manufacturer, and serves as a rich reference point in developing a project or scheme.

architecture news

keep up with our daily and weekly stories
492,044 subscribers
- see sample
- see sample