A maple bonsai occupies a small volume of growing medium, so the conditions around its container deserve as much attention as the canopy. A sheltered-looking balcony can still expose the pot to reflected heat and drying wind.
Check where sun reaches the plant through the day and whether surrounding walls or paving intensify the exposure. A position suitable earlier in the season may change as the sun's angle and weather change.
Water from the root conditions
Inspect moisture carefully rather than responding only to a wilted leaf. Do not assume every damaged leaf means the tree needs another watering.
Keep the tree's identity, potting history and local climate in mind when choosing its position. Avoid a major pruning or leaf-removal operation simply because an online seasonal calendar lists one for that month.
If you move the tree to a better position, document the change and watch subsequent growth. Old damaged leaf tissue may remain visible. The goal is a suitable continuing environment for the roots and foliage, not an immediate cosmetic result that requires repeated intervention.
The RHS bonsai guide notes that small, shallow containers hold limited water and can dry quickly in warm, windy weather. It also treats pruning as species-specific, rather than one operation for every miniature tree.
Related reading: Maple Bonsai Care: Position, Watering, Feeding and Pruning.