Mastering ます-Stem Endings: 〜やすい, 〜にくい, 〜かた, and 〜すぎる

Welcome to your comprehensive guide to one of the most versatile and high-scoring grammar patterns in Pearson Edexcel A Level Japanese (9JA0)! Suffixing verbs to modify their meaning is a core skill tested across Paper 1 (Translation and Reading), Paper 2 (Translation into Japanese and Essay Writing), and Paper 3 (Listening and Summarisation).

Don't worry if verb stems and endings seem tricky at first. Once you master the underlying foundation—the ます-stem—these four suffixes follow logical, consistent patterns that will instantly boost your range and grammatical accuracy.

Step 1: The Foundation — Verb ます-Stem (連用形 Ren'yōkei)

Before attaching any of these four endings, you must strip your verb down to its ます-stem (also known as the pre-ます form or 連用形 ren'yōkei). Let's review how to create this stem for each verb group:

1. Group 1 Verbs (Godan / Consonant-Stem Verbs):
Drop the final dictionary -u vowel and shift it to the corresponding -i row.
• 書く (kaku) \( \rightarrow \) 書き (kaki)
• 飲む (nomu) \( \rightarrow \) 飲み (nomi)
• 使う (tsukau) \( \rightarrow \) 使い (tsukai)
• 話す (hanasu) \( \rightarrow \) 話し (hanashi)

2. Group 2 Verbs (Ichidan / Vowel-Stem Verbs):
Simply drop the final る (-ru).
• 食べる (taberu) \( \rightarrow \) 食べ (tabe)
• 見る (miru) \( \rightarrow \) 見 (mi)
• 覚える (oboeru) \( \rightarrow \) 覚え (oboe)

3. Irregular Verbs:
Memorise these two essential stems:
• する (suru) \( \rightarrow \) し (shi)
• 来る (kuru) \( \rightarrow \) 来 / き (ki)

Key Takeaway: Always isolate the pure ます-stem first. Attaching suffixes directly to the dictionary (plain) form (e.g. kaku-yasui) is an immediate error in the exam!

1. 〜やすい (-yasui) — Ease of Action & Propensity

Meaning & Nuance

When attached to a verb stem, 〜やすい expresses two major ideas:

1. Physical or Practical Ease ("easy to do"): The action can be performed smoothly, comfortably, or without difficulty.
Example: この薬は飲みやすいです。
(Kono kusuri wa nomiyasui desu. — This medicine is easy to take/swallow.)

2. Tendency or Propensity ("prone to / likely to"): Describes something that has a natural habit or tendency toward a certain state.
Example: この時期は風邪をひきやすい。
(Kono jiki wa kaze o hikiyasui. — One is prone to catching colds during this season.)

Grammatical Behaviour: It Acts as an い-Adjective!

The moment you attach やすい, the whole compound behaves exactly like an い-adjective (i-adjective).

• Non-past affirmative: 読みやすい (yomiyasui — easy to read)
• Non-past negative: 読みやすくない / 読みやすくありません (yomiyasukunai / yomiyasukuarimasen — not easy to read)
• Past affirmative: 読みやすかった (yomiyasukatta — was easy to read)
• Past negative: 読みやすくなかった (yomiyasukunakatta — was not easy to read)
• Adverbial form (〜く): 読みやすく書く (yomiyasuku kaku — to write legibly / so it is easy to read)
• Noun-modifying form: 使いやすいパソコン (tsukaiyasui pasokon — an easy-to-use computer)

2. 〜にくい (-nikui) — Difficulty & Resistance

Meaning & Nuance

〜にくい is the direct antonym of 〜やすい. It conveys:

1. Physical/Objective Difficulty ("hard/difficult to do"): Something is tough to do because of the inherent physical properties or characteristics of the object.
Example: この字は小さくて読みにくい。
(Kono ji wa chiisakute yominikui. — These characters are small and hard to read.)

2. Resistance to Change ("hard to / unlikely to"):
Example: 割れにくいガラス。
(Warenikui garasu. — Shatter-resistant / hard-to-break glass.)

Grammatical Behaviour: Also an い-Adjective!

Just like 〜やすい, 〜にくい inflects strictly as an い-adjective.

• Non-past affirmative: 読みにくい (yominikui — difficult to read)
• Non-past negative: 読みにくくない (yominikukunai — not difficult to read)
• Past affirmative: 読みにくかった (yominikukatta — was difficult to read)
• Past negative: 読みにくくなかった (yominikukunakatta — was not difficult to read)
• Adverbial form: 読みにくく (yominikuku)

Key Takeaway for 〜やすい and 〜にくい: Treat both endings as standard い-adjectives when conjugating for tense, politeness, or negation. Never conjugate them like verbs!

3. 〜かた / 〜方 (-kata) — Way or Method of Doing

Meaning & Syntax

Attaching 〜方 (かた) transforms an action verb into a noun that means "how to do", "way of doing", or "method".

• 使う (to use) \( \rightarrow \) 使い \( \rightarrow \) 使い方 (tsukaikata — how to use / method of use)
• 読む (to read) \( \rightarrow \) 読み \( \rightarrow \) 読み方 (yomikata — way of reading / pronunciation)
• 作る (to make) \( \rightarrow \) 作り \( \rightarrow \) 作り方 (tsukurikata — recipe / method of making)

The Crucial Particle Replacement Rule: を \( \rightarrow \) の

Because `[Verb stem] + 方` becomes a noun phrase, standard transitive verbs cannot keep the direct object particle を (o). You must replace を with の (no) to connect the preceding noun to the new compound noun.

Standard Rule:
\( [\text{Noun}] \text{ を } [\text{Verb}] \implies [\text{Noun}] \text{ の } [\text{Verb stem}] \text{方} \)

Step-by-step Transformation:
1. Original sentence action: 漢字を覚える (kanji o oboeru — to memorise kanji)
2. Form the verb stem: 覚える \( \rightarrow \) 覚え (oboe)
3. Attach 方: 覚え方 (oboekata)
4. Change particle を to の: 漢字の覚え方 (kanji no oboekata — how to memorise kanji)

Key Takeaway: Whenever you see `〜方` in translation or essay writing, double-check that you used の instead of を!

4. 〜すぎる / 〜過ぎる (-sugiru) — Excessiveness ("Too Much")

Meaning & Formation

〜すぎる means "to do too much", "over-do", or "too [adjective]". Unlike the other patterns, 〜すぎる can attach to verbs, い-adjectives, and な-adjectives.

1. With Verbs (ます-stem + すぎる):
• 食べる \( \rightarrow \) 食べ \( \rightarrow \) 食べすぎる (tabesugiru — to overeat)
• 飲む \( \rightarrow \) 飲み \( \rightarrow \) 飲みすぎる (nomisugiru — to drink excessively)

2. With い-Adjectives (Drop final い + すぎる):
• 高い (expensive) \( \rightarrow \) 高 \( \rightarrow \) 高すぎる (takasugiru — too expensive)
• 辛い (spicy) \( \rightarrow \) 辛 \( \rightarrow \) 辛すぎる (karasugiru — too spicy)
• CRITICAL IRREGULARITY: いい / よい (good) \( \rightarrow \) よすぎる (yosugiru — too good). Never say "iisugiru"!

3. With な-Adjectives (Stem / Drop な + すぎる):
• 静か[な] (quiet) \( \rightarrow \) 静かすぎる (shizukasugiru — too quiet)
• 簡単[な] (simple) \( \rightarrow \) 簡単すぎる (kantansugiru — too simple)

Grammatical Behaviour: It Acts as an Ichidan (Group 2) Verb!

Regardless of whether it attached to an adjective or a verb, the final compound `〜すぎる` conjugates strictly as a Group 2 (Ichidan) verb:

• Plain non-past: 食べすぎる (tabesugiru)
• Polite non-past: 食べすぎます (tabesugimasu)
• Plain past: 食べすぎた (tabesugita)
• Polite past: 食べすぎました (tabesugimashita)
• Negative: 食べすぎない / 食べすぎません (tabesuginai / tabesugimasen)
• て-form (cause/reason): 食べすぎてお腹が痛い (tabesugite onaka ga itai — I overate and my stomach hurts)
• Noun form: 食べすぎ (tabesugi — overeating)

Key Takeaway: 〜すぎる is a verb. Do not conjugate it like an adjective (e.g. avoid tabesugikatta; always use 食べすぎた).

Examiner Pitfalls & Common A Level Mistakes

Be on high alert for these five frequent errors flagged in examiner reports:

1. Attaching Endings to Dictionary Forms:
❌ kaku-yasui / taberu-sugiru
✅ 書きやすい (kakiyasui) / 食べすぎる (tabesugiru)

2. The "を" Particle Trap with 〜方:
❌ 本を読み方 (hon o yomikata)
✅ 本の読み方 (hon no yomikata — how to read the book)

3. Part-of-Speech Confusion:
• やす・にく compounds are い-adjectives: Say 使いにくいです (tsukainikui desu), never tsukainikimasu.
• すぎる compounds are Group 2 verbs: Past plain is 飲みすぎた (nomisugita), never nomisugikatta.

4. The Irregular いい / よい with すぎる:
❌ いいすぎる (iisugiru)
✅ よすぎる (yosugiru)

5. Nuance: にくい vs. 難しい (muzukashii):
Use 〜にくい when the difficulty stems from physical handling, inherent characteristics, or functional resistance (e.g. small font being hard to read). Use 難しい as an independent adjective for conceptual or intellectual difficulty (e.g. a difficult exam).

Quick Revision Summary

• Stem Requirement: All 4 suffixes require the ます-stem (連用形) of the verb.
• 〜やすい (i-adj): Easy to do / prone to doing.
• 〜にくい (i-adj): Hard to do / resistant to doing.
• 〜方 (Noun): Way/method of doing. Remember: Noun + の + [Stem]方.
• 〜すぎる (Group 2 Verb): Excessive degree ("too much"). For adjectives, drop final -i or -na. Remember いい \( \rightarrow \) よすぎる!