Writing in English from the outset
It is good for non-native English speakers to write in English from the outset if they are proficient enough in English to express the relations between parts of sentences and they have enough time to do this. They will be more likely to use English logical flow when writing and will also include fewer direct "translations" from their native language.
See our previous Featured Article Writing naturally in English: Strategies for authors writing in a second language for more information and tips on the actual process of writing naturally in English.
Do I need English editing before submitting my manuscript?
If your grammar is good enough to express the relations between concepts/things both within sentences and between sentences, then your message should be understandable. When you check through your English manuscript and finish self-editing, you may decide that your message will be understood by the reviewers: If they can quickly and easily understand your main message and supporting evidence, even with some grammar mistakes in your writing, then you might decide to submit.
If the journal editor can understand your paper clearly even with some mistakes, the paper will usually enter peer review. Peer reviewers, as long as they can clearly understand your scientific content, will review the paper. They may then ask you to fix the English errors before resubmission. The key here is that no-one should have to do a lot of work to understand your message.
So, the point is whether the reviewers will be able to understand your English easily. If they might not understand, then consider asking a colleague who is good at English or a specialist native editor to help you improve the clarity of your paper before submission.
If you are asked to revise your paper based on the reviewers' comments, then be prepared to produce English at least as good after revision as it was before it. So, when checking your revised paper, you should ask yourself again whether you need English editing. You might need to ask for help from an English-speaking colleague or a specialist native editor.
Another consideration is whether the journal offers copy-editing of accepted papers, to fix English errors and follow a house style. Some journals, such as PLOS ONE, do not perform any copy-editing. For those journals, we recommend that you have either comprehensive editing or proofreading performed before you submit your revised paper.
Last but not least, we want to mention the time available for writing. Even good writers can produce work with errors in it when they are rushed. This can be magnified when writing outside their native language.
If you are short on time, think about the trade-off between writing quickly, but maybe not clearly, in English and writing quickly in Japanese and explaining your scientific message accurately and clearly. This is for you to judge whether you'll need English editing (or not) or Japanese-to-English translation.
Our team can often complete highly technical work very quickly, with our EXPRESS services. So, if you're not sure what to do, please do talk to us and we'd be happy to help you decide what's best in the circumstances.
Using both strategies: writing in your native language and in the target language
There may be times when you want to combine the strategies of writing in your native language (e.g., Japanese) and writing in the target language (e.g., English). We're happy to support you in this through providing both translation and editing services in a "mixed project."
Example 1: You had your English paper edited before submission and now you are in a hurry to write your revised paper. You can write the new parts of your manuscript in Japanese and we can translate them and make them fit coherently and consistently with the original text.
Example 2: You are writing a new paper for submission in English and find you are running out of time. You complete the paper in Japanese. We'll comprehensively edit or proofread the English text, depending on the level of editing you need, and translate the Japanese text, linking them together coherently and consistently.