---
id: janome
version: "0.5.0"
license: AL2
license_treatment: permissive
maintenance: active
---

# Janome — Japanese morphological analysis engine.

License: permissive · Maintenance: active · Downloads: 380.3K/mo

## What it is and what it does

Janome is a morphological analyzer for Japanese text that runs entirely in Python without external compiled dependencies. It tokenizes Japanese sentences and annotates each token with part-of-speech tags and grammatical information using the MeCab-IPADIC dictionary. The package is designed for developers who need to process Japanese text in Python applications without installing system-level NLP tools.

The analyzer works by segmenting Japanese text (which lacks spaces between words) into meaningful tokens and providing linguistic metadata for each. It's used in search, text mining, and NLP pipelines where understanding the grammatical structure of Japanese is necessary. The package has been actively maintained since 2015 and remains in beta status.

Use it for:

- Tokenize Japanese text for search indexing or full-text search applications.
- Extract part-of-speech information for Japanese language NLP tasks like sentiment analysis or text classification.
- Build Japanese text preprocessing pipelines for machine learning models that require morphological features.
- Analyze Japanese documents to identify nouns, verbs, and other grammatical elements for content analysis.
- Segment Japanese user input in chatbots or voice assistants before semantic processing.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Janome is a Japanese morphological analyzer written in pure Python that breaks Japanese text into tokens with part-of-speech and grammatical annotations.

Yes, if you need to process Japanese text in Python. Janome is a mature, actively maintained, permissively licensed tool with no known vulnerabilities and low install friction. It's the right choice for projects that require Japanese morphological analysis without external system dependencies. Not relevant for non-Japanese text processing.

## Install

pip install janome
uv add janome
poetry add janome

## Installing Janome

Before you install: Low install friction; the package is a pure Python wheel. Note that building from source consumes about 500 MB of memory during installation.

License in practice: Licensed under Apache License 2.0 (permissive). The package also uses the MeCab-IPADIC dictionary and statistical model; see LICENSE.txt and NOTICE.txt for full details.

Quickstart:

pip install janome

from janome.tokenizer import Tokenizer
t = Tokenizer()
for token in t.tokenize('すもももももももものうち'):
    print(token)

Python 3.7+ is required.

Verify before relying:

- Whether the MeCab-IPADIC dictionary license imposes additional constraints beyond Apache 2.0 for commercial use.
- Current memory requirements for typical production workloads beyond the noted 500 MB build-time consumption.
- Performance characteristics and throughput on large-scale Japanese text processing tasks.

## Package facts

- License: AL2 (permissive)
- Python support: unspecified
- Install friction: low
- Maintenance: active
- Downloads: 380.3K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

japanese text tokenization, japanese morphological analysis, japanese nlp tokenizer, japanese word segmentation, japanese pos tagging, japanese language processing, japanese-nlp, text-tokenization

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