ましょうか details
write + shall I…?
kaki mashou ka
shall I…?; shall we…?
meaning: shall I write
ちょっと暑いですね。窓、開けましょうか？
chotto atsui desu ne. mado, ake mashou ka?
It's a bit hot in here — shall I open the window? neutral
お時間です。そろそろ始めましょうか。
o jikan desu. sorosoro hajimemashou ka.
It's time — shall we begin? formal
Examples
shall I…? — offering to do something for the listener
ちょっと暑いですね。窓、開けましょうか？
chotto atsui desu ne. mado, akemashouka?
It's a bit hot in here — shall I open the window? neutral
駅まで迎えに行きましょうか。
eki made mukae ni ikimashou ka.
Shall I come pick you up at the station? neutral
shall we…? — nudging a shared, expected action into motion
お時間です。そろそろ始めましょうか。
o jikan desu. sorosoro hajimemashou ka.
It's time — shall we begin? formal
Formation
{V-masu-stem}ましょうかattaches to ます-stem
Notes
Related patterns
Similar
手伝いましょうか offers the speaker's help, 手伝いませんか asks for the listener's — ましょうか proposes what the speaker will do or what is already on the table, ませんか recruits the listener into something new.
Lookalikes
One か apart — ましょう declares "let's", ましょうか opens a question ("shall I?" / "shall we?"); dropping the か by accident turns an offer of help into a decision already made.