Forming ます Across the Classes | Japanese Grammar

You already know that ます carries politeness and that it rides on a short stem. This page is the mechanic's manual: how to build that stem from any verb, class by class. The rule reduces to a single instruction — get the い-row stem, then add ます — and the only thing that actually varies is how godan verbs make their stem. Master that one kana shift and every polite form in the language falls out.

The one-line rule

ます-form = い-row stem + ます.

Godan verbs: change the final う-row kana to its い-row partner.
Ichidan verbs: drop the final る.
Irregular verbs: する → し, 来る（くる）→ 来（き）.

That is the whole system. Everything below is just filling in the godan kana table, which is where beginners lose points.

Godan verbs: shift the last kana up to the い-row

Godan verbs end in one of nine kana, all from the う-row of the kana chart (う, く, ぐ, す, つ, ぬ, ぶ, む, る). To make the ます-stem, slide that kana straight down its column to the い-row: う→い, く→き, ぐ→ぎ, す→し, つ→ち, ぬ→に, ぶ→び, む→み, る→り. Then add ます.

Ends in	→ い-row	Dictionary	Stem	ます form	Meaning
う	い	買う（かう）	買い	買います kaimasu	to buy
く	き	書く（かく）	書き	書きます kakimasu	to write
ぐ	ぎ	泳ぐ（およぐ）	泳ぎ	泳ぎます oyogimasu	to swim
す	し	話す（はなす）	話し	話します hanashimasu	to speak
つ	ち	待つ（まつ）	待ち	待ちます machimasu	to wait
ぬ	に	死ぬ（しぬ）	死に	死にます shinimasu	to die
ぶ	び	遊ぶ（あそぶ）	遊び	遊びます asobimasu	to play
む	み	飲む（のむ）	飲み	飲みます nomimasu	to drink
る	り	帰る（かえる）	帰り	帰ります kaerimasu	to go home

Two of these hide a pronunciation surprise you must respect in romaji even though the kana is perfectly regular:

す → し is written shi, not "si": 話します is hanashimasu.
つ → ち is written chi, not "ti": 待ちます is machimasu.

The kana column is regular; Japanese just spells those two syllables with an English-unfriendly consonant. Say them as they sound.

ちょっとここで待ちます。

chotto koko de machimasu

I'll wait right here for a bit.

駅で切符を買います。

eki de kippu o kaimasu

I'll buy a ticket at the station.

毎晩、日記を書きます。

maiban, nikki o kakimasu

I write in my diary every night.

友達と公園で遊びます。

tomodachi to kōen de asobimasu

I'll hang out with friends at the park.

Ichidan verbs: just drop る

Ichidan (る-dropping) verbs are the easy class. Their stem is the dictionary form minus る — no vowel gymnastics. Add ます and you are done.

Dictionary	Stem	ます form	Meaning
食べる（たべる）	食べ	食べます tabemasu	to eat
見る（みる）	見	見ます mimasu	to see, to watch
起きる（おきる）	起き	起きます okimasu	to get up
教える（おしえる）	教え	教えます oshiemasu	to teach

週末に映画を見ます。

shūmatsu ni eiga o mimasu

I'll watch a movie this weekend.

毎朝六時に起きます。

maiasa rokuji ni okimasu

I get up at six every morning.

💡

The one danger with ichidan verbs is telling them apart from godan verbs that also end in る (帰る, 走る are godan). If you are unsure which class a る-verb belongs to, see identifying ichidan vs. godan verbs. Guess wrong and 帰る (godan) becomes ×帰ます instead of the correct 帰ります.

The two irregulars

There are exactly two irregular verbs in Japanese, and their ます-stems simply have to be memorized:

Dictionary	Stem	ます form	Meaning
する	し	します shimasu	to do
来る（くる）	来（き）	来ます kimasu	to come

The trap with 来る is the reading: the kanji 来 is read く in the dictionary form but き in 来ます. The character does not change, but its sound does — so 来ます is kimasu, never "kurumasu."

友達が明日来ます。

tomodachi ga ashita kimasu

My friend is coming tomorrow.

毎日、宿題をします。

mainichi, shukudai o shimasu

I do my homework every day.

The insight: ます-formation is the mirror of ない-formation

Here is what ties the godan table together and makes it stick. The plain negative form (〜ない) uses the very same slot in the verb, but shifts the final kana to the あ-row instead of the い-row. Same position on the kana ladder, different rung:

Verb	あ-row → ない (negative)	い-row → ます (polite)
書く	書か + ない → 書かない	書き + ます → 書きます
飲む	飲ま + ない → 飲まない	飲み + ます → 飲みます
待つ	待た + ない → 待たない	待ち + ます → 待ちます
買う	買わ + ない → 買わない	買い + ます → 買います

Notice the う-verb: its negative goes to わ (買わない, a spelling quirk you can read about in forming the negative ない), while its polite stem goes cleanly to い (買います). Once you picture the godan verb as sliding up and down a single vowel ladder — あ for negatives, い for ます — the two "lists" collapse into one system. Learn them together; they are two doors in the same wall, described fully in the godan sound rows.

Common mistakes

❌ 買あます

Wrong — う shifted to the あ-row (the negative's slot), not the い-row.

✅ 買います

kaimasu

Correct — う-verbs go to い for ます. あ is only for the negative 買わない.

❌ 待つます

Wrong — the つ was never shifted.

✅ 待ちます

machimasu

Correct — つ shifts up to ち.

❌ 話すます

Wrong — す was left in place.

✅ 話します

hanashimasu

Correct — す shifts to し (spelled 'shi').

❌ 見るます

Wrong — an ichidan verb kept its る.

✅ 見ます

mimasu

Correct — drop る, then add ます.

❌ するます

Wrong — する was not converted to its irregular stem.

✅ します

shimasu

Correct — する's stem is し.

Key takeaways

The universal rule is い-row stem + ます.
Godan: slide the final kana down its column to the い-row (う→い, く→き … る→り), then add ます.
Ichidan: drop る, add ます.
Irregular: する → します, 来る → 来ます (kimasu, with the reading change).
The い-row shift for ます is the exact mirror of the あ-row shift for the negative ない — one vowel ladder, two forms.

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