Okihama

...It was established because it was a rocky beach but had an abundance of fuel in the surrounding area. A stone wall was piled up about 3 to 5 meters high, the inside was filled with soil and rubbish, and the top was hardened by mixing matsuchi (pure soil) and sand, and then mountain clay was laid down and tamped to make an impermeable ground, on which sand was spread. Because of this shape, it is also called "Okihama". This was relatively efficient as there was no waste of seawater. ...

*Some of the terminology that refers to "Okihama" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…岩石浜であるが周辺に燃料が豊富であるという条件で成立したもので，3～5mほど石垣を積み，内側を土砂･塵芥で埋め，その上部を真土（まつち）と砂を混じて固め，さらに山粘土を張り，突き固めて不透水地盤とし，この上に撒砂を撒布する。こういう形態であるため〈置浜〉ともいわれる。これは海水にむだがなく比較的効率がよかった。…

※「置浜」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報