Rules -- Bridged Series

Bridged Series was invented by the Japanese puzzle company Nikoli (under the name Hashiwokakero).

1. Draw horizontal and vertical bridges (diagonal bridges are not allowed) between the islands according to the following rules.
2. A number on an island indicates how many bridges are connected to that island.
3. At most two bridges can connect a pair of islands.
4. A bridge may not cross over an island or another bridge.
5. All of the islands must be connected via the bridges. (It must be possible to get from any island to any other island using the bridges.)