In the preceding section, the common space ratio of a number of examples was analysed. On Gunkanjima, however, not only was the common space ratio higher than elsewhere, the public realm was arranged and used in such a way as to compensate for the restricted size of the living space. Incidentally, compared with apartments elsewhere containing the same number of rooms with the same number of tatami mats, the apartments on Gunkanjima have an appreciably higher total floor area. This was because the architects made use of the Kyo-ma System of tatami arrangement whereby the tatami multiples correspond to internal dimensions of a room and exclude the thickness of structural members such as pillars. The fact that the designers had little experience of fitting Japanese tatami rooms into a reinforced concrete structure paradoxically turned out to be an advantage, resulting in the creation of generous pockets of additional space around the periphery of the rooms. As an example, let us consider the Nikkyu Flats (buildings No. 16 – 20, erected in Taisho 7 – 1919 – as company lodgings to house daily-wage laborers). Taken together, these buildings constitute the largest complex of units put up before the war, and from the point of view of form and construction, they are typical of the apartments built on Gunkanjima. (see Fig. 2.3 ~ 5)

The large corridors of the Nikkyu Flats overlooking the sea were built with the following functions in mind:

1)To act as passages connecting each of the five buildings which made up the complex, and as reverse-setbacks cut into the steeply sloping rock face behind the flats at right angles to form terraces, because of the nature of the site.

2)To protect the residential area from the sea.

In fact, however, these passages were in effect typical common space used for various purposes besides those envisaged by their designers. As circulation area, they served not only the interior of the Nikkyu Flat complex, but also functioned as a principal trunk route serving the island as a whole. Other uses may be listed as follows:

1)For drawing water until the completion of the submarine waterworks in Showa 32 (1951). A wellside chat was an important form of social intercourse for many housewives.

2)For an afternoon nap or for enjoying the cool of the evening as a refuge from the high temperature and high humidity within individual flats in summer.

3)As playgrounds for children, especially for infant, where they learned social standards and conventions by being together with adults.

4)For washing clothes etc, and drying them when it was raining.

5)For D.I.Y. activities and repair of domestic appliances etc.

6)As spaces for open assemblies like open spaces or 'pocket-parks' in conventional towns and, at festival times, as grandstands for viewing events at Hashimaginza which the Nikkyu complex overlooked.

7)For putting ip notices on information boards etc.

The weatherbeaten corridors along the front of the Nikkyu Flats thus correspond, as it were, to the alleys of downtown tenement buildings. Unlike the apartment houses developed in Europe, the high rise apartment houses on Gunkanjima may be interpreted as traditional rows on tenements (nagaya) superimposed one above another as an experiment in exploiting the potential of the new structural material, reinforced concrete, in order to make optimum use of the limited land available. A Japanese traditional tenement house has essentially only one room. Not only did they have public toilets, wells and washing places, but even the kitchen was outside under the eaves. It follows that without alleys giving access to an unfloored area of each apartment, a tenement house could not have been convenient to line in.

On Gunkanjima, as time went by, kitchens and later toilets came to be placed indoors. Finally in the high-class apartment houses a bath was provided in each flat. In the case of the Nikkyu Flats, all basic service facilities apart from the kitchen were communal and the large corridors provided access to them.

An individual flat in a tenement house was not in itself a complete living space. Some activities which we usually consider a part of private life took place outside regardless of the size of each apartment. It was therefore necessary for people to coexist amicably with neighboring families. To establish an acceptable modus vivendi, a set of rules and conventions for autonomic living were required including those concerned with cleaning or other daily maintenance. It was clear from the replies to our questions both in interviews and in the questionnaire that a body of such rules and conventions existed on Gunkanjima. We shall not discuss them in detail here except to note that they concerned cleaning rotas and consideration of the fact that daily routines governed by 3 different working shifts had to co-exist. The open corridors in front of the apartments acted in concert with an unfloored area within each apartment. This unfloored area was private and functioned as a drying place, a washing place, a place for the washing machine, a place for flower pots and jars, a place for cooking, and a place for other utilities. At the same time the corridors were public routes connecting the high-land at the top of the cliff with the main road along the sea front in the shopping district. (On Gunkanjima there were no roads of constant width conforming to highway legislation, apart from imaginary ones which existed only on paper to satisfy the authorities. Their true spatial character can perhaps best be described as amorphous). This combination of unfloored area within each flat and the open corridor with its facilities together completed the living environment. The open corridor in front of the apartment was quite literally semi-public space.

According to our data, among the side-corridor type buildings, those that have the corridor within the structural frame have higher common-space-ratios. Qualitatively too, a corridor separated by columns has bays the width of a column, and this space can easily be used for private purposes or as a corner in which to stop for a chat with neighbors. Technical developments led to the introduction of the cantilevered side-corridor type which made its appearance in Showa 14 (1939). It was structurally more reined, had lower construction cost, and a more rationalised waterproofing and drainage system. However, when the way in which the buildings were used and the proportion of semi-public space available are considered, it appears that the more traditional the building type, the better was the sense of community which it promoted.