score:9
While there are some not very widely supported theories out there that postulate some somehow Jewish origin for Columbus (esWP: Cristóbal Colón, Origen, Hipótesis secundarias, enWP: Catalan-Jewish hypothesis) this even if 'true' is not saying much about his beliefs and writing practices.
The claim to investigate here says very explicitly:
At the top left-hand corner of all but one of the 13 letters written by Columbus to his son Diego contained the handwritten Hebrew letters bet-hei, meaning b'ezrat Hashem (with God's help).
And he did mark his letters in a peculiar way:
– Christopher Columbus autograph letter written to his son Diego on 5th February 1505
Most clearly seen in this version (to Diego, 18th January 1505)
— (Beth and hei in the top left-hand margin.) On a site that promotes to see the matter as settled: 'Columbus being from Ibiza'…
Or another take on his handwriting
— Columbus Manuscript: In this manuscript, enscribed Cadiz, Spain, November 20, 1493,
So, in Hebrew the letters supposedly used are Aramaic/quadratic script:
ה ב
and in the letters (many facsimiles in The authentic letters of Columbus, 1895) we see this:
How much this resembles Hebrew lettering?
In cursive handwriting (albeit quite modern)
Wikipedia has a handwriting style for cursive Hebrew letters including in Spain and those dated 1480:
The above may also be compared to Solitreo and Ladino scripts that use these alphabets for perhaps a Judeo-Spanish hand
A modern letter using the acronym at the top of a letter (note that it is top right though):
But the question asks for "see with own eyes"…
Therefore I will refrain from judging the theories of origin for Columbus, here, or whether it is indeed the claimed letter combination. Just that using a certain symbol, even if it should be the claimed one, is not and cannot be the 'final proof that he was a Jew', or somehow of Jewish Origin. At best, this might add a little detail for some circumstantial evidence.