Forms
Each verb or adjective has ten different forms. It seems overwhelming but you can handle all of them by understanding how to make them with the charts below.
| Irregular verb forms | Weak verb forms | Strong verb forms |
| Being verb forms | い adjective forms | な adjective forms |
Irregular verb forms
There is no rule for Irregular verb. That is why it's called "Irregular", but you would be fine if you remember the forms for the two main Irregular verbs, する (do) and くる (come).
| Form | する (do) | 来（く）る (come) |
| plain present positive form | する (do) | 来（く）る (come) |
| plain present negative form | しない (don't/doesn't do) | 来（こ）ない (don't/doesn't come) |
| plain past positive form | した (did) | 来（き）た (came) |
| plain past negative form | しなかった (didn't do) | 来（こ）なかった (didn't come) |
| polite present positive form | します (do) | 来（き）ます (come) |
| polite present negative form | しません (don't/doesn't do) | 来（き）ません (don't/doesn't come) |
| polite past positive form | しました (did) | 来（き）ました (came) |
| polite past negative form | しませんでした (didn't do) | 来（き）ませんでした (didn't come) |
| て form | して | 来（き）て |
| stem form | し | 来（き） |
Weak verb forms
The chart below tells you how to make each form from plain present positive form.
| Form | How to make | Example |
| plain present positive form | a word in a dictionary | 食（た）べる (eat) |
| plain present negative form | cut off る, then add ない |
食べ る → 食べ ない (don't/doesn't eat) |
| plain past positive form | cut off る, then add た |
食べ る → 食べ た (did eat) |
| plain past negative form | cut off る, then add なかった |
食べ る → 食べ なかった (didn't eat) |
| polite present positive form | cut off る, then add ます |
食べ る → 食べ ます (eat) |
| polite present negative form | cut off る, then add ません |
食べ る → 食べ ません (don't/doesn't eat) |
| polite past positive form | cut off る, then add ました |
食べ る → 食べ ました (did eat) |
| polite past negative form | cut off る, then add ませんでした |
食べ る → 食べ ませんでした (didn't eat) |
| て form | cut off る, then add て | 食べ る → 食べ て |
| stem form | cut off る | 食べ る → 食べ |
Strong verb forms
The chart below tells you how to make each form from plain present positive form.
| Form | How to make | Example |
| plain present positive form | a word in a dictionary | 読（よ）む (read) |
| plain present negative form | Change the last symbol into "a" sound, then add ない | 読 む → 読 ま ない (don't/doesn't read) |
| plain past positive form | Change the last symbol following the rule here | 読 む → 読 んだ (did read) |
| plain past negative form | Change the last symbol into "a" sound, then add なかった | 読 む → 読 ま なかった (didn't read) |
| polite present positive form | Change the last symbol into "i " sound, then add ます |
読 む → 読 み ます (read) |
| polite present negative form | Change the last symbol into "i " sound, then add ません |
読 む → 読 み ません (don't/doesn't read) |
| polite past positive form | Change the last symbol into "i " sound, then add ました |
読 む → 読 み ました (did read) |
| polite past negative form | Change the last symbol into "i " sound, then add ませんでした |
読 む → 読 み ませんでした (didn't read) |
| て form | Change the last symbol following the rule here | 読 む → 読 んで |
| stem form | Change the last symbol into "i " sound |
読 む → 読 み |
Being verb forms
Being verbs (or, the verb to be) are is, am, are, was and were.
| Form | だ（is, am, are） |
| plain present positive form | だ (is, am, are) |
| plain present negative form | じゃない (isn't, am not, aren't) |
| plain past positive form | だった (was, were) |
| plain past negative form | じゃなかった (wasn't, weren't) |
| polite present positive form | です (is, am, are) |
| polite present negative form | じゃないです (isn't, am not, aren't) |
| polite past positive form | でした (was, were) |
| polite past negative form | じゃなかったです (wasn't, weren't) |
| て form | で |
| stem form | n/a |
い adjective forms
The chart below tells you how to make each form from plain present positive form.
| Form | How to make | Example |
| plain present positive form | a word in a dictionary | 安（やす）い (is/am/are cheap) |
| plain present negative form | cut off
い, then add くない |
安 い → 安 くない (is/am/are not cheap) |
| plain past positive form | cut off
い, then add かった |
安 い → 安 かった (was/were cheap) |
| plain past negative form | cut off
い, then add くなかった |
安 い → 安 くなかった (was/were not cheap) |
| polite present positive form | cut off
い, then add いです |
安 い → 安 いです (is/am/are cheap) |
| polite present negative form | cut off
い, then add くないです |
安 い → 安 くないです (is/am/are not cheap) |
| polite past positive form | cut off
い, then add かったです |
安 い → 安 かったです (was/were cheap) |
| polite past negative form | cut off
い, then add くなかったです |
安 い → 安 くなかったです (was/were not cheap) |
| て form | cut off い, then add くて |
安 い → 安 くて |
| stem form | cut off い | 安 い → 安 |
な adjective forms
な adjectives have な at the end when you find them in a dictoinary. The chart below tells you how to make each form from it.
| Form | How to make | Example |
| plain present positive form | cut off
な, then add だ | 静か な → 静か だ (is/am/are quiet) |
| plain present negative form | cut off
な, then add じゃない |
静か な → 静か じゃない (is/am/are not quiet) |
| plain past positive form | cut off
な, then add だった |
静か な → 静か だった (was/were quiet) |
| plain past negative form | cut off
な, then add じゃなかった |
静か な → 静か じゃなかった (was/were not quiet) |
| polite present positive form | cut off
な, then add です |
静か な → 静か です (is/am/are quiet) |
| polite present negative form | cut off
な, then add じゃないです |
静か な → 静か じゃないです (is/am/are not quiet) |
| polite past positive form | cut off
な, then add でした |
静か な → 静か でした (was/were quiet) |
| polite past negative form | cut off
な, then add じゃなかったです |
静か な → 静か じゃなかったです (was/were not quiet) |
| て form | cut off な, then add で | 静か な → 静か で |
| stem form | cut off な | 静か な → 静か |
