Longjing and its flat leaf
Longjing's flattened leaf is distinctive, but the best introduction is the relationship between its shape, aroma and cup.

A leaf that lies flat
Longjing, also written as Dragon Well, is a Chinese green tea recognised for its flattened leaf shape. Rather than forming needles or tightly rolled pellets, the leaves lie in slender, relatively flat pieces. That makes the dry tea unusually easy to inspect. You can notice differences in size and colour without pulling apart a rolled ball. But the neatness of the leaf is only one feature, and a handsome arrangement on a tray cannot replace tasting the actual tea.
The aroma is often a useful clue
Pan heating is part of Longjing's production, and the finished tea is often associated with gentle nutty or chestnut-like impressions alongside fresh green notes. Those descriptions do not mean nuts have been mixed into the packet. They also do not require every cup to taste strongly roasted. A restrained warmth can sit underneath the fresher aroma. If you only search for one advertised flavour, you may miss the balance that makes a particular lot enjoyable.
The name has a strong association with the Hangzhou area and the West Lake tradition. Products sold under the wider name vary, so precise origin information matters when provenance is part of what you are paying for. Shape alone cannot authenticate a geographical claim.
Let a small serving tell you more
Use the seller's preparation guidance and keep the first serving plain. Smell the dry leaf, then the damp leaf after pouring. In the cup, notice whether the flavour remains clear as it cools and whether the finish feels smooth or drying. These observations are more useful than demanding that every Longjing have exactly the same shade of green.
After the infusion, lay a few leaves on a saucer. The flattened pieces soften and make their structure more apparent. This is a good moment to connect the processed shape with the original leaf, not to conduct a rigid beauty contest. A practical first purchase is a small amount with a clear description, enough for several cups so that one imperfect preparation does not become your entire opinion of the style.