One side reservation - Ippono Yoyaku

...There are two types of reservations when a reservation right holder attempts to establish a contract: (1) those in which the other party is obligated to consent, and those in which the contract is established immediately without consent (i.e., those in which the right to complete the reservation is recognized). And, (2) depending on whether the reservation right holder is one of the parties (which is common) or both, (1) is usually divided into unilateral reservations and bilateral reservations, and (2) into "unilateral reservations" and "bilateral reservations." The parties can choose any of these four types. ...

*Some of the terminology explanations that refer to "one-sided reservation" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…予約には，予約上の権利者が本契約を成立させようとする場合に，(1)相手方が承諾の義務を負うものと，承諾なしにただちに本契約が成立するもの(すなわち，予約完結権を認めるもの)との2種がある。そして，(2)予約上の権利者が当事者の一方であるか(これが多い)，双方であるかによって，普通は，(1)が片務予約と双務予約に，(2)が〈一方の予約〉と〈双方の予約〉に，分かれる。当事者はこの4種類のいずれを選ぶこともできる。…

※「一方の予約」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