Mitsubishi G3M 九六式陸上攻撃機 Rikko (Allied code name Nell)
Mitsubishi followed the Japanese military preference for an aircraft design with range and speed above all else which meant sacrificing defensive arms as well as a structure which could absorb damage and seal sealing fuel tanks. For a bomber of the time this was not unusual as much modern thinking of the day had bombers all but invincible to flak as well as fighters—multiple engines giving them speed and altitude over single engine aircraft.
That was the thinking of the 1920s and 1930s, thinking which would prove lethally outmoded in the 1940s. A more graceful aircraft of the day is hard to find even after modification to include gunners and their positions. Ultimately the Nell would have seven crew members which included 1 x 20mm cannon and 4 x 7.7mm machine gun positions. The Nell had long legs but was not speedy and was so prone to becoming alight from enemy fire that her crews nicknamed the type “Flying Cigar” though Nells were effective in numbers early in WW II.