We now have two pieces of credible information on the Chinese air raid on Taiwan in Feb, 1938 (cf previous post here and for more information by Patrick Cowsill, here).
In the 新竹新聞網Hsin-chu News website, Mr 宋建和, a Hsin-chu native, has written a short memoir "憶兒時─螢雪時代往事知多少", in which, he recalls:
1. The date of the air raid was Feb 22, 1938 [not Feb 23], and it occurred around noon time;
2. The targets were 松山Song-Shan [Matsuyama] Military Airfield in Taipei and the oil fields in Chu-tong竹東 員崠子油井 [not Hsin-chu Airfield];
3. The siren sounded only after the bombers (of an unknown number - "several" was mentioned) left which were earlier attacked by two [Japanese] fighters;
4. News reports from China and Taipei differed, especially the damages to the oil fields, extensive and none, respectively; and
5. The Sunday after the bombing, the author's father led the family to visit the bombed site, and the oil rigs appeared undamaged.
There you have it then: Chu-tong, not Hsin-chu was bombed but suffered no damages.
As for the date of the air raid, Dr 黄称奇 in his memoir "末代の二等兵" recounted, "... 但し、支那事変以来としては、昭和13年、の2月22日が最初、中国空軍に依る、新竹油田、台北松山飛行場...", i.e., the first ever air raid on Taiwan by the Chinese Air Force was on Feb 22, 1938, targeting Hsin-chu [should have been Chu-tong] oil fields and 松山 Airfield.