Translation guide
How to express switching allegiance, changing one's position in a conflict, or physically moving to the other side in Japanese.
To abandon one's group, team, or cause and join the opposing side.
Literally 'to turn over in sleep', this is the most common and natural way to say 'change sides' in the sense of betraying one's group and joining the enemy. Often used in historical, political, or competitive contexts.
彼は敵側に寝返った。
He went over to the enemy side.
選挙の直前に、数人の議員が野党に寝返った。
Just before the election, several lawmakers defected to the opposition party.
Means 'to betray'. It implies a breach of trust, not necessarily physically joining the other side, but often used when someone switches allegiance.
彼は味方を裏切って敵に情報を流した。
He betrayed his allies and leaked information to the enemy.
Literally 'to change saddles', this is a somewhat dated or literary expression for switching sides or changing one's affiliation, especially in politics or business.
彼は政権交代の際に鞍替えした。
He switched sides when the administration changed.
To go from one side of a physical space to the other.
A straightforward way to say 'move to the opposite side'. Use this for physical movement.
道路の反対側に移りましょう。
Let's move to the other side of the road.
Literally 'go to the other side'. Casual and common for physical movement.
川の向こう側に行きたい。
I want to go to the other side of the river.
To switch from supporting one argument to supporting the opposite argument.
Means 'to change one's position/stance'. Suitable for formal or informal contexts when someone shifts their viewpoint.
議論の途中で彼は立場を変えた。
He changed his stance in the middle of the debate.
Literally 'to flip one's opinion', this implies a sudden or dramatic change of mind. Somewhat formal.
社長は急に意見を翻して、その計画に反対した。
The president suddenly changed his mind and opposed the plan.
Do not translate 'change sides' literally as 側を変える (がわをかえる). This sounds unnatural and is not used for switching allegiance. Use 寝返る or 裏切る instead.