Unassisted writing means writing in the target language without any tools — no dictionary, no grammar checker, no AI help. Just you and your brain.
Unassisted writing is a focus on fluidity and getting words out onto the page. It also reveals holes in your knowledge (words you can't remember, unclear grammar constructions, accurate expression of ideas), but leaves a trace in the way speech doesn't. You can't hide behind unclear pronunciation. Each word is on the page, spelled out, which also makes it perfect for review.
It also builds fluency of expression. Without the option to look things up, your brain is forced to work with what it has — retrieving words, constructing sentences, and expressing ideas from memory. This is the same skill you need for speaking.
Just write. Journal entries, stream-of-consciousness, descriptions of your day, reactions to something you read. Don't worry about mistakes — the goal is volume and fluency, not accuracy. If you don't know a word, try to express the idea differently. If you're not sure about grammar, go with your gut.
A spell checker isn't really a tool, but it's still better to turn it off for this. You get fewer angry red squiggles jumping out at you.
Unassisted writing is introduced in Phase 5A alongside assisted writing.